Well ... usually German tanks had 3 Numbers of their turrets. The numbers meant company, platoon, vehicle. So a tank with the number 323 would have been from the 3rd company, 2nd platoon, 3rd vehicle. There were variations. For example Tiger I companies had the letter S followed by two numbers painted on their turrets. S23 for example. That meant
Schwer (heavy), 2nd platoon, 3rd vehicle. Some used the S for Stabskompanie (Headquarter Company) ... Tiger I batallions used the 0 for their HQ companies, for example S02 = heavy, HQ, 2nd vehicle.
Supposedly a vehicle of the 15. PzDiv in Tunesia in 1942
No number at all .... and this bugger only got one number but a spade too ...
And to make matters even worse, there were no strict orders on which numbers to paint on the turrets. Even the colors varied. So honestly I think you should look up some pics on the internet and take them as reference if you want to be historically correct. Or you can just make up some numbers following the above guidelines.
Hope this helped.