help for a musically naive person

I am a minister and occasionally I lead worship in a seniors care home. When it comes to leading the hymn singing, sometimes I have a pianist to assist me and sometimes I am on my own. When on my own I can manage if I have a hymn book with the music, and I am familiar with the tune. I find some of the hymns too high for my voice, so I installed Musescore with the idea that I would use it to lower the hymns, print the lowered music and take it to the worship service. I am now trying to learn how to use the program. I loaded some music and tried out the transpose feature. All I am interested in doing is lowering the pitch by one or two notes till it is in a range I am comfortable in. But when I open the transpose function, I have no idea how one tells it to lower everything by one or two notes. Not being a musician, I don't understand terms like "augmented unison" or "minor second". I don't know what "closest" key signifies. If I just want lower everything by a note or two, what should I do?
Thanks for any help. The seniors I help thank you too.
Arthur