Converting Piano Midi to Tab

Open the file in MuseScore
Right click the staff select Staff/part properties and click the change instruments button (above the long instruments name) choose guitar and click OK. Check the results to make sure they look like guitar music. Press i to open the instruments dialog. To the right of the piano is a gray dropdown that says "Standard" click that and choose a 6 string tab type that you want. This should be a good starting point for converting it directly from piano to guitar. You will need to make some changes if the guitar part is impossible.