As others have said, youtube. There are several videos that will help with just about anything you can think of. Just search for DCS A-10C training or tutorial. I've been flying the sim for about 3 weeks now and I've been able to learn the more in depth stuff the in-sim training doesn't cover by watching videos.
I made a mission with some trucks and tanks as targets to practice what I watched. No SAM/AAA threats so I can buzz around in orbit to practice stuff with no fear of getting shot down. No JTAC to help but I obviously know where I put my targets, but it still helped using the TGP to pinpoint them and set markpoints, etc.
