@ShadowKiller105 They mean that if you're on chrome click the puzzle piece up on the search bar and click "run all plugins this time" and then you'll be able to load them. You do have to click that every time you play the game if you want to load players made things though.
@ChompyFishy If you're on chrome, you can click the little puzzle piece by the bar where you type in stuff then click "Run all plugins this time" It should work. But you will have to click it every time you enter the game if you want to load levels and items.
I second this! Pump up the stars and vote this comment up!! Keep a look out for a big update next week(ish) with new content :)