How to answer this tricky English question

[@PeterchazzGodday]

Pls sir help me differentiate between Their’s and Theirs…also any other words or beings or been. Plsss sir

[@englishbydgargantuan1825]

@@PeterchazzGodday Okay, I will make a video of them right away.

[@PeterchazzGodday]

@@englishbydgargantuan1825 thank you sir…God bless you sir.

[@PeterchazzGodday]

Also when to use has,have and had..