Working with vocal sounds

Hello -- I am brand new to MuseScore and have started experimenting with the choral template.
I have edited staff properties (staff label) from S-A-T-B to S1-S2-A1-A2 for a women's choir arrangement. I've started with the A1 line. Using MIDI input, the notation appears an octave higher than it should be, so I use CTRL-down arrow to correct that. However, the A1 line continues to sound like tenor/bari voices. For that same part, I've also attempted to "change instrument" as well....some instruments produce no sound at all, others a distorted sound, and if I choose "soprano" the sound seems to be transposed somehow.
How can I get the former "tenor" line to sound like an alto voice?
Please forgive my "newbie" ignorance...any helpful hints would be greatly appreciated. Thank you.