Q: How does the photo sharing thing work? What if I don't wish to share my photos?

Then don't share.

fcardel wrote:

 

How does the photo sharing thing work? What if I don't wish to share my photos?

You manage what you share.

Use iCloud Photo Sharing

Use the Photos app to create a shared album that shows the photos you choose. Invite up to 100 of your favorite people to join in, make comments, and even add their own shots. Then you can manage your shared album and permanently save any photos that your friends add.

These articles may help understand Photo Sharing:

iCloud: iCloud Photo Sharing overview

iCloud: Set up iCloud Photo Sharing

iCloud Photo Sharing - Apple Support