It's unbelievable! Or is that its?

This is going to be a quick and easy post. Mainly because I was unable to work on my computer all day (stupid malware!) and I need to get the kids to bed. So, refresher course on "it."

IT is a pronoun, used to replace a noun in the sentence.
Which shows the correct form of a possessive "it?"
Maude put the book on its side.
Maude put the book on it's side.

If you said the first sentence, kudos to you! In this ONE case, the possessive does not use an apostrophe s. It'S has a COMPLETELY different meaning.

"Its about time you got here."
"It's about time you got here."

What is the correct form in this sentence? If you said "It's" another kudos--you got this down!

It's ALWAYS means IT IS (or it has). It never means the possessive of it. So, only use it to mean it is (or it has).

Are you using it correctly? If you can stick an "It is" into the sentence and it still makes sense, then yes.

Maude put the book on [it is] side. Nope. Makes no sense. So the it in this sentence would be its.
"[It is] about time you got here." Yep! Got it! So that one should be it's.

See? That isn't so bad.