Mistake(?) in grammar

Selamun aleykum everyone,
In the rule below it says that adding a meem(م) to the end of a verb makes it second person plural. But shouldn’t it be -tum instead of just meem for the “you all” Version of the verb. Instead of using you and y’all versions I think it would be clearer to use just the base verb فعل at the top and the “you all” Version in the bottom and highlighting -tum.( sorry it sounds so weird probably, I couldn’t explain myself very well, but I hope you will understand what I am saying) jazakum Allahu khairan.

Both are accurate. You can attach a meem at the end of a ha, a ta, or a kaf. All of that turns it into plural.

Oh okay than, thank you for the clarification