The plugin we use for claiming land is Lands. Claiming is enabled in the overworld, nether, and the Badlands but is disabled in Resource World and The End.
A feather can be used to identify if a chunk is claimed and a golden hoe can be used for selecting an area. Commands associated with Lands can be found here.
You can obtain Claim Chunks by claiming your 3 hour /rewards. You get 1 claim chunk every 3 hours. You also have a chance of getting Claim Chunks by opening the Vote Crate. They currently have a 25% chance to drop, but this may be increased in the future. You can have a maximum of 1,500 Claim Chunks.
Lands will fall according to incremental playtime. The breakdown: