How do you show possession in a sentence grammatically?

There are several correct ways to show possession.

You can use possessive pronouns such as my, mine, your, yours, his, hers, its, our, ours, their and theirs.

The book is mine. The ball is yours. My book and your ball are in his locker.

You can make a noun possessive by adding 's to the end (just add ' to Words that end with an s, including most plurals).

Bob's book is in Ross' locker. The teacher's lunch is in the teachers' lounge.

You can use the preposition of.

The equipment of the football team is in the equipment locker.