ArchitectMCYour first claim
A claim is a 16×16 chunk that only you (and people you trust) can build in. Stand where you want the house, then type /claim. /claims opens the same thing in a chest menu.
The two-chunk gap
You cannot claim right next to someone else’s land. Keep two empty chunks between you and a stranger. Your own claims can touch each other.
How many chunks
New players start with a small limit. Rank up by playing and you can claim more. If the server says you are at your limit, you need a higher rank — not a bug.
Friends
Stand in the chunk and use /trust <name>. That person can build and use things on that chunk only. /untrust takes it back.
Leaving
/unclaim drops the chunk you are standing in. Do not unclaim a shop you still want.