I am entering information for my 1098-T. In the section for books and materials required and not required, is this where I add supplies, electronics, gas, etc?

Yes, and no.  Generally, a laptop or computer would be required so that would be in the required part.  If you purchased headphones for a class  or other electronics, then you could enter that there. You will only enter actual items that you bought for school that the school did not require you to buy.  For example, if you have e-books and you wanted the hardback books.  Then you would enter that there.

You do not add gas or food or things like that anywhere.