Fortnite - Why only one place available?

Ji, I've been wondering all the time, why no one in Fortnite comes to me! And now I finally know it:

How can I change this?

You can always join friends then you can play in pairs or more depending on the 0/1 means that none of your server on your island plays that changes automatically when several join

You can't change that yourself.

If no one is on your server, then your island is 0/1.

Joint a friend your server is available when he wants to your island 1/2.