Hi, and welcome to LFS... Say goodbye to your regular life, because you won't be seeing it for a while
The BEST way to start is by taking the XFG out for a drive. It's front wheel drive, and slow as my grandma on a scooter, but it's the perfect car to learn carcontrol in. Then, when you're confident you can keep her on the road and keep up with the AI, you may want to go for some different type cars which are not too powerful, just to feel the difference between FWD, RWD, 4WD, etc. Do all of this on one track, like Blackwood.
Once you get to grips with the XFG and the way the G25 works for you, start learning other tracks, and get online to join in some races. Make sure you know the car and track before you join though, we don't mind slower drivers, as long as they are coming prepared.
Also, there's a list of things you should check out in the threads in this forum that are stickied at the top. They'll help you prepare yourself for everything you'll find in the world of LFS. Find some setups you feel comfortable with, and find some nice people who can help you gain speed and teach you how to race. You'll find that there are a lot of helpful people online.
But remember the most important thing you should always do while you're a part of LFS... And that is to have FUN.
I know that I made it sound like a very long process, but you'll be online and racing us in no time at all, it's easy
C ya online soon!