linking mandolin notation with mandolin tabular staffs

Follow the Handbook instructions here: https://musescore.org/en/handbook/3/create-new-score#choose-template. When you come to "Chose instruments", make sure you bring up the "All instruments" list (i.e. not just the "common ones"). You'll find Mandolin and Mandolin (Tablature) in there. A little further down the Handbook instructions describe how to add a linked staff: https://musescore.org/en/handbook/3/create-new-score#add-staff

Once you have the basic score set up to your liking you can save it as a custom template.