How set in your world or server:
Step 1: Download a schematic.
Step 2: Put in "schematics" carpet
Step 3: Reload the plugin with "/we reload" or "/worldedit reload"
Step 4: Select a location.
Step 5: Use "/schem load mountain-with-lagoon" command in-game.
Step 6: Paste the tree with "//paste" command.
Step 7: Beware with the Mountain with lagoon, needs a considered space.
Be careful! Your server may fall because the mountain with lagoon is very big.