Newbie question on track numbers

Stupid newbie question probably.

My track numbers are a mess. More often than not, it says x/0, where x is the correct track number (1 digit or 2 if above 10) and 0 is the wrong number of total songs on the disc.

How do I change this in a fast and easy way or is it not important? If you use Discogs, it will autofill, but only with the first number, 1 instead of 1/15 for example.

nevermind, this is solved
found the track wizard in extra menu