Manual Installation
1. Download the .
2. Open MuseScore and go to Edit>Preferences. Locate the path to the Plugins folder.
3. Extract the contents of the downloaded zip file and move them to the path you found in step 2.
4. In MuseScore, go to Plugins > Plugin Manager and click Reload Plugins
5. On the left, make sure MuseLab is checked, then press "OK."
6. You're all set! To use MuseLab, click on Plugins > MuseLab.