If you are the owner, you have all permissions

If you want to invite:

Owners can invite anybody

Admins can invite writers or readers

Writers can invite readers

To Admin is to read, write, invite readers or writers

To Write is to read, write, invite writers

If you can Write, you can create private documents

You can Read if:

You are a owner, admin, writer

OR if none of the parent documents

See if you have permission to <Read/Write> for the current doc.

You can comment if you can Read, and if you have Joined the site or any parent document.

A Join is a contact that you publish

If you have been given a Capability but have not joined, you have not accepted the role