Example: '/land claim grow up 16' would expand your currently active claim 16 blocks to the sky.
/land claim add -- add your current active selection to the area you want to claim as a whole (must always do before finishing with '/land claim save').
/land claim cancel -- cancel the process and discard all changes.
/land claim save [name] -- save everything and name your claim.
/land claim load [land list id] -- load and modify an existing claim.
/land list -- lists all your claims with id numbers.
/land info -- if inside a claimed area, shows info about the owner and set privileges.
/land claim grant [playername] [use/all] -- grant another player interact or building privileges.
/land claim grantgroup [groupname] [use/all] -- grant an group interact or building privileges.
/land claim allowuseeveryone [true/false] -- grant interact privileges to everyone (use with caution).
/land claim revoke [playername] -- revoke granted privileges to an player.
/land claim revokegroup [groupname] -- revoke granted privileges to an group.
/land free [land list id] -- unclaim your land, if not in use anymore.
How to claim a piece of land - Full example:
Open the chat window with 'T', write '/land claim new' and hit the 'Enter' key. Now move your character to the position you want your area to start from. Write '/land claim start', hit 'Enter'. Move your character to the end position of your future claim. Write '/land claim end', hit 'Enter'. A claim can consist of multiple areas. You just created one.
We are not finished yet. Now, we have different choices: If you are happy with the dimensions, we could add the area with '/land claim add' and continue to add more areas or just save the claim with '/land claim save NAME' to finalize it. But since you probably want to at least expand your just created area a bit more up or down, we will first modify the dimensions of that area with '/land claim [direction] [value]', e.g. '/land claim grow up 16', if you would want your area to be 16 blocks higher than it is now.
You may cancel the process any time with '/land claim cancel'.