In order to expand your land you will need to click on the hammer icon that is surrounded by a border on your land.
This will open the expansion screen and show you what resources are required and the time required for your next plot of land
Each new piece of land is an NFT that is minted onto your farm
You can watch the progress with the timer as the goblins work hard.
Once complete, check back to see what resources you have available. Each land uses RnG to procedurally generate what resources are available on your new land. The more you progress, the better the chances of finding something rare.