Copyrights and use of musescore downloads

I recently downloaded Popcorn – Hot Butter and also Hernando’s Hideaway from musescore. I didn’t see any copyright information on the Popcorn download and only “all rights reserved” on Hernando’s Hideaway. Do I have a right to take those scores and arrange them for small ensembles for use in a non-commercial way at a retirement home. I have no intention of publishing anything or of charging admission or in any other way making money. We just want to be able to play these arrangements. Is this legal, particularly for the two pieces I mentioned? Did I miss something regarding copyrights when I downloaded? I would appreciate your clarification on this problem. I use Finale to write out my arrangements, so I really don’t need the music writing part of musescore. Do I need to pay a membership, or can I just download the music I need? Thank you for your help.