How do I add part names at the start of the stave?

Hi - I'm new to MuseScore - and not the most technically intuitive person, so I'm afraid there is a lot of swearing going on this morning.

Can anyone help me? Although I selected, voice, keyboards & drumset when I set up the new score, only Drumset is labelled at the start of the line (full title first line, then abbreviated) and I can't work out how to do the same for the Keyboard and voice parts. I've found related listings searching through the forums - but none of the solutions seem to work for me (I think some are for the older version).

Thanks in advance for helping to reduce my blood pressure!