I'll try and explain so you can stop moaning about a skill that is ultimately pointless for a wizard.
On this server you can tame things 1 level lower than its own level. Taming here lasts forever or until they die. Your pets gain experience relative to you, so if you kill something with a lot of experience, they share that experience and will level up quickly. Do not go around taking them to kill low exp mobs because that's not how it works on these files.
I'm going to be blunt with you taming is pointless up until level 43 where you can tame BlueFrogs in foxcave. You could make the argument for the yellowfrogs too, I suppose at level 35, but they're both bugged on here and walk towards the target to attack rather than away from the target, making them a pain in the ass to manage. They'll eventually wonder off and die to something at some point if you don't constantly keep an eye on them. They are at best a one time use tool in PvP to win-over a fight, or a means to kill a boss quicker. Ultimately, you are better off levelling with FW-Lightning on this server for the rest of your days.