The most recent version of the Sage Advice Compendium will contain a list of links to errata for individual books
Wizards do not maintain a single up-to-date reference page which lists all the current errata or how to find it. However, their Sage Advice Compendium PDFs contain a list of links to the most recent (as of publishing) errata documents for all official 5e products; the best way to find errata is to check the most recent version of the SAC, revisions of which should be published in articles in the "Sage Advice" section of the WotC website.
As a general rule, most errata documents are announced/published in Sage Advice articles before being referenced in updates to Sage Advice Compendium, and those articles are not obviously updated when later errata affecting the same resources is published (though the files they link to may change to newer versions without notice). In some cases Wizards have announced new errata solely by announcing a new SAC version with the new links, as in the November 2020 update. The December 2021 update announced new errata while simultaneously linking to a new version of the SAC (and, despite calling it a Sage Advice article, didn't actually put it in the Sage Advice section of their site).
This all makes trying to search the internet for relevant errata quite annoying, especially as the order in which the articles are indexed by search engines does not necessarily put the most recent version at the top of the list.
(It must also be noted, as per Akixkisu's answer, that the official errata documents do not actually document all of the changes in text that have been introduced in newer printings of some 5e books, including changes that some consider significant.)
As of this edit, the most recent version of the Sage Advice Compendium is v2.7 (~December 2021), but this will undoubtedly be superseded in the future. The list of errata links from this version is reproduced below.
ERRATA
Errata have been issued for certain fifth edition books and can be downloaded at the following locations.
Player’s Handbook
https://media.wizards.com/2021/dnd/downloads/PH-Errata.pdf
Monster Manual
https://media.wizards.com/2018/dnd/downloads/MM-Errata.pdf
Dungeon Master’s Guide
https://media.wizards.com/2021/dnd/downloads/DMG-Errata.pdf
Curse of Strahd
https://media.wizards.com/2021/dnd/downloads/CoS-Errata.pdf
Eberron: Rising from the Last War
https://media.wizards.com/2020/dnd/downloads/ERftLW-Errata.pdf
Ghosts of Saltmarsh
https://media.wizards.com/2020/dnd/downloads/GoS-Errata.pdf
Hoard of the Dragon Queen
https://media.wizards.com/2016/downloads/DND/HotDQ-Errata.pdf
Mordenkainen's Tome of Foes
https://media.wizards.com/2020/dnd/downloads/MTF-Errata.pdf
Out of the Abyss
https://media.wizards.com/2020/dnd/downloads/OotA-Errata.pdf
Princes of the Apocalypse
https://media.wizards.com/2016/downloads/DND/PotA-Errata.pdf
Storm King’s Thunder
https://media.wizards.com/2021/dnd/downloads/SKT-Errata.pdf
Sword Coast Adventurer’s Guide
https://media.wizards.com/2021/dnd/downloads/SCAG-Errata.pdf
Tales from the Yawning Portal
https://media.wizards.com/2021/dnd/downloads/TftYP-Errata.pdf
Tasha's Cauldron of Everything
https://media.wizards.com/2021/dnd/downloads/TCE-Errata.pdf
Tomb of Annihilation
https://media.wizards.com/2021/dnd/downloads/ToA-Errata.pdf
Volo’s Guide to Monsters
https://media.wizards.com/2021/dnd/downloads/VGtM-Errata.pdf
Xanathar's Guide to Everything
https://media.wizards.com/2020/dnd/downloads/XGtE-Errata.pdf
For those interested in reviewing the history of the SAC, the answers to this question include a list of links to archived versions of the SAC and some examination of the changes between them.
Having recently played a Pathfinder one-shot where half of the players were completely new to the system; many of them were confused, including our normal D&D 4E DM. Character creation alone took around an hour and a half due to the wide variety of options. Despite this, once we actually started playing things rolled along decently quickly. Based on this experience, I can certainly recommend a few things to avoid.
Avoid too Many Options
Option paralysis is a very real thing even for experienced players; when someone is just starting out with Pathfinder, they lack the ability to make an assessment of important skills, feats, and variant classes or alternate class features available. I'd recommend letting the players in question choose their race and class and whipping up a set of recommended Feats and Skills they should take to prevent this paralysis; keep the character building aspect simple at first. If you had a lot of time on your hands, you might even make two or three of these recommendation sheets per character and let the player choose between them; this would serve as a simplified introduction to feats and skills. You can do something similar with spells for spellcasters. It's worth stating that these options are important to Pathfinder; it's just important to introduce them slowly. If you wanted to go even further, you could recommended against prepared spellcasters and make them keep to spontaneous spellcasters to keep their options low. I would also recommend against Summon type spells, since they usually require the player to have a detailed knowledge of all the creatures on the Summon List.
Keep it Low Level
No, lower level than even that. I'd recommend starting around level 1 or 2; higher than that, and the feat and spell choices multiply quickly. We all played as Level 4 Monk variants in our one-shot, and feat selection alone took the bulk of our character creation time.
Make sure your Players know what they can do In Play
Depending on familiar your players are with other editions of D&D, many of these concepts might not need to be explained. Other than the obvious attack and damage rolls, make sure fighter-type classes know what their feats actually do; give them a sheet with the descriptions of their feats on it. You should be able to make sure your players understand the action system as well. With spellcasters, I would recommend printing off a sheet of their prepared spells to let them know what options they have immediately available to them. For all players, make sure they know what their class abilities are; if their options are described on their character sheets and can be quickly refereed to, they're more likely to learn them. Readily available descriptions for Feats, Spells and Class Abilities will reduce confusion at the table
All of these are pointing to one thing: Reduce Complexity. Your players will understand Pathfinder better when they aren't immediately thrown into the deep end of interlocking mechanics, build choices, and combat options. If you present options as they come up (or let players read and discover for themselves between sessions), your players will be less overwhelmed and have more fun.
Best Answer
The Rules Compendium has all the updated rules for the core system, like changes to skills and skill challenge DCs and whatnot. You should pick that up if you don't mind buying another book.
Changes to the races and classes are pretty specific. Do you mind editing the question to list what your players are planning to play?
I think the biggest change outside of specific power tweaks to the classes in the first Player's Handbook is that a rogue can apply his Sneak Attack damage once per turn rather than once per round.