/f claim – Claim the land where you are standing
/f claim [faction=your] [radius=1] – Claim the land in a radius around where you are standing
/f autoclaim [faction=your] – Start auto-claiming land as you walk around
/f unclaim, declaim – Unclaim the land where you are standing
The area claimed is a minecraft “chunk”. It is an 16×16 area all the way from bedrock to the sky. If you are claiming territory from another faction you must start at the border. Only faction moderators and admin can do this.