Here is a link to the "getting started" Wiki.http://www.bogleheads.org/wiki/Getting_Started
There is a lot of great information in the books and links but you have plenty of time to learn. Since you will be starting out with a relatively small amount making all the best choices right now isn't nearly as important as avoiding really bad choices.
Here are some fairly safe generic recommendations that will be good enough to get you started but you will likely want to revise these some when you learn more.
1) The maximum 401k contribution for 2013 for someone your age is $17,500 a year and you will want to save that in the 401K. Since you are starting out near the middle of the year you will need to figure out what contribution per paycheck it will take to come close to that total by the last paycheck in December. You don't want to reach the maximum too early in the year since some employers calculate the match each paycheck so if you reach the maximum in November you might not be able to make any contributions in December so you could miss out on getting a match that month.
There will likely be a target date fund in the 401K that is based on your probable retirement age, like a 2050 fund. Put all your 401K money into that for now. These are not perfect but they are a fine choice while you learn more and not a bad choice even when you do know more.
Next January you will need to reduce the 401K contribution amount so that you reach the maximum in December of next year too.
2) Save up $5,500 to make a Roth IRA or Traditional IRA contribution by next April 15. You may be on the borderline of being able to make a deductible IRA contribution for 2013 but you can figure all the details on this out next spring before you do your taxes since you will be able to make 2013 contributions up until April 15th of 2014.
3) Save up some out of each paycheck to build up an emergency fund for unexpected expenses. You will want to get it up to three months expenses pretty quickly and eventually build it up to 6 month expenses.
4) Save up some out of each paycheck so that you will have enough to pay cash for your next car.
It would be good to open up separate accounts for these funds and have the money automatically deposited from each paycheck.
5) Commit to saving half of any bonus or pay raise. This will make saving a large percentage of your income easy and you will never miss the money. This is what I did (mostly anyway
) and this one thing made a huge difference in how well I was able to do financially.
6) This may seem counter intuitive but you might also want to have a modest amount( maybe 3% or so) of each paycheck deposited into a separate account for your "fun" money for things like travel. By having a separate account this will help keep you from blowing too much on splurges but it will also help you balance the "now vs. later" question.