Things are, indeed, a little scattered in the Requiem core book, a consequence of being one of the first books to hit shelves for the nWoD. A later book, called simply The Blood, organizes things better.
To answer your question: The prospective sire kills, and probably exsanguinates, the prospective childe. At the moment of death — the "right" moment for dramatic purposes — the Sire feeds the childe a point of Vitae and burns a dot of permanent Willpower to empower the magic that causes the victim to rise as a vampire. The point of vitae spent engenders the Blood Sympathy and a first-rank Viniculum.
The usual answer to "how much blood is in a newly created vampire?" is "none" or "however much of his sire's blood is expended in the creation."
Mechanically, I think there are really only three big differences.
First is that spending a point of Willpower in Requiem grants you three extra dice on the roll rather than an automatic success, which is a very big deal.
Next is that botching (or "dramatic failure") just doesn't happen as often in the new World of Darkness system. Dramatic failures only occur when you are reduced to rolling a chance die (one die that only succeeds on a roll of 10) and it comes up a 1.
A relatively minor difference related to that is that success really isn't measured in degrees in the new system. You either succeed or you get an exceptional success. The Storyteller has to declare bonuses or penalties (which grant or remove dice) prior to the roll.
The third big difference is that in combat, damage is figured directly from the result of the attack roll. It's faster, but it can be a lot deadlier.
In terms of the story, the Masquerade setting is gone. Requiem focuses much more closely on local action compared to Masquerade's global tone. Clan infrastructures like the Nosferatu's intelligence network just don't exist, and most vampires align themselves with philosophically like-minded covenants.
If you never played Masquerade as anything but a city game, I don't think you'd find it much different. There are some interesting changes to how the vampiric condition works, though. They get more powerful with age thanks to Blood Potency, so lineage doesn't matter as much. Also, vampires instinctively recognize the Beast in each other using a system called the Predator's Taint.
White Wolf has published a good translation guide for playing Masquerade with Requiem or vice versa.
I'm actually using that guide to run my Masquerade game using Requiem's rules.
Hope that helps!
Best Answer
White Wolf halted their fiction line a couple years back. I believe they are starting to release some new fiction via PDF/POD thru DriveThruRPG.