Go to the "Levels" tab and click blue button "Add level". Next choose "create album" and upload your level.
Sure We've completed a document that gives more details than the short instructions above. I will send you a link in a private conversation. Hopefully you can give us feedback to see if any changes need to be made prior to publishing it to this site. UPDATE: The "How to Share a Mekorama Level" document has been posted for all here! @Benjamin Panzuelo Rubrico and others, please let us know what you think of this document. Thanks.