Make a shortcut of Blockland on your desktop, then right click it, and in the Target are that says "C:\Program Files\Blockland\Blockland.exe"
Put ' -mod editor' (Without the 's) at the end of the file path, it should then look like this
"C:\Program Files\Blockland\Blockland.exe" -mod editor
Then use the shortcut, start a multiplayer or singleplayer server and when you spawn, hit F11, hit F4 to go to the menu where you spawn stuff, but here's a tip, hit the button up top that says World, then choose Drop at Camera