Let's review the basic numbers first, before we get into how Wizards break them: at level 1, every character picks 2 at-wills, 1 encounter power, and 1 daily. At level 2, they pick up a utility power too.
At-will powers
So, you have to choose two at-wills, right?
But there's something else first. Some classes have feature powers, and the Wizard's are their four cantrips. You get these automatically. You already have four at-wills, just by being a Wizard.
These do not count toward the 2 you pick. So pick two more Wizard Attack 1 at-wills.
Notice that the Cantrips have no level mentioned. Neither do Racial powers. This is your hint that it's an automatic feature that you get in addition to however many at-wills/encounters/dailies/utilities you get at your level. (The Paladin also has four class feature powers, but two of those are encounter powers.)
Total level 1 at-wills: 6. And then some racial features might give you more.
Encounter powers
1 at first level. Gain encounter powers the same as any other class.
A lot of races also give you an encounter power, but like I mentioned about the at-wills: this comes in addition to whatever single encounter power you pick, and doesn't count toward your limit of 1.
The Spellbook: Dailies and Utilities
This is where Wizards have some novelty, and where they get a bit complicated.
Every class has a notion that they have X powers and they have them available every day. Wizards break this mold and do things very differently.
When the Wizard might learn a daily or utility power — including their first-level daily and second-level utility — instead, the Wizard picks two dailies, or two utilities. They write these two down in their spellbook. Then as the feature says...
After an extended rest, you can prepare a number of daily and utility spells according to what you can cast per day for your level. You can’t prepare the same spell twice.
You pick a bunch, and these are your daily and utility powers for the day. So you know twice as many daily powers and twice as many utility powers as any other class. But at the beginning of your adventuring day, you pick the same amount as anyone else, and those are your dailies and utilities for the day.
So at level 2, instead of the usual 1 daily and 1 utility, you'll have twice that many - 2 dailies and 2 utility powers - written in your spellbook. But after you rest, you'll pick 1 of those dailies and 1 of those utility powers, and you'll have those available to use for the day. So on any given day, you still have access to the same amount of daily and utility powers as any other character - but uniquely, Wizards can change the powers they have access to day-to-day between those in their spellbook.
At a level where you might be alotted 3 daily powers, you'll have 6 in your spellbook, and pick any 3 of those 6 at the beginning of an adventuring day. Etc.
Rituals
You also get to start with some rituals written in your spellbook. This is separate to your powers entirely, and a different casting system every player character shares. You just get to start off knowing some rituals, where others will have to find them or buy them.
Best Answer
Power points are spent to augment the Psion's at-will powers. Each Psion at-will power has the keyword augmentable, and a number of additional clauses in the text that tell you what to do based on how many points you spend to use the power. By default the expenditure is 0.
As far as a list of powers for Psions, your best bet is the Wizards DDI compendium. Even if you are not a subscriber the search functionality is quite helpful to find the source locations for each power and for creating lists of things (for instance you can filter the entire powers list to Psion, At-Wills). There is also the Psion Char-Op Guide, which as with all the Char-Op guides is recommended reading and has a complete list of power selections and some helpful strategies for building a character.
Psions do not get a spell book, they get powers just like everyone else, the spellbook is a uniquely wizard exception. They do not get regular encounter powers, just At-Wills, Utilities and Dailies. Psions can and do take feats to give them ritual caster abilities that are contained in a ritual book, but that's neither here nor there with respect to power points.
Just so it's perfectly clear, Psions trade their encounter powers for encounter renewing power points which effectively model and follow an incredibly similar progression to regular AEDU class encounter powers. There is no real change in the power balance structure here.