Old Timer, these guys have given you great advice, and well, I can't help u with ur present problem with the button for a race line, but I do have some advise.
When I first got the simulator, I spend a good amount of time using the training, from the main menu. It really really helps, for some more than others, but if you're new to racing, and don't know much about it, the training can teach you quite a bit, for some ppl it's a real must. I didn't really need it because I do race in real life (for fun not pro lol) and it actually did help me, because it is still a simulator, and every bit of practice pays off. I highly recommend spending time in the games training, it may help you. It's not the best training they could possibly have mad, but it's well done, and actually pretty fun when the simulator is still new to you, enjoy, and welcome to LFS, the best, most realistic racing simulator ever made!