Can I make new materials, and if so how? I'll really appreciate any help I can get. Thanks. (I've already tried to add a new one in materials, but it keeps crashing. I think it may have something to do with the index, but I'm not really sure.)

Copy and paste an existing material, one that is close to what you want to make.
Edit it however you want.
Give it a name that isn't already taken, a color that isn't already taken, and an index number that is not already taken.


Available Index numbers are: (dashes meaning 'to')
4-7, 13-15, 19-47, 51-127, 130-135, 137-143, 149-159, 165-175, 182, 183, 185-191, 194-207, 210-223, 226-254

Thanks