Im starting my first season in Leahy. I purchased a second season already. So when should I schedule my non conference games for next season?

Anytime...but it has to be completed by the end of the National Championship game.  I suggest scheduling at least a couple of SIMs, then depending on how you think you can do, a couple of human coached teams that you think you can beat.  The conference schedule will be set for you and you won't know what it is until after the season rolls over.

Keep in mind 'vision' ... it corresponds to roughly your last 3 years win totals.  You definitely want to make sure to keep increasing.  Don't bite off more than you can chew.

For your first couple seasons schedule a sims you need the wins!

Keep your schedule weak until you make the playoffs, then start increasing it a bit at a time.