You have to look for levels on the steam threads or on reddit though. It is still in beta so they don't have a steam workshop thingie up and running yet.
It should work fine but if there's any issues such as the level not loading or the game crashing then edit the level and select "Save" and then play the level, it usually fixes a CTD.
Level editor is after all still in beta. So it has a number of issues, but once a level is finished and properly tested to work then it should work without any hicups.