How do I move a note up or down on the save quickly

Most interesting. I have tried it and cannot get it to work. I must be doing something wrong. This is what I am doing. 1. Open Notation Composer. 2. Click on 'Create New Song'. 3. Click time signature etc until the page appears before me. 4. Click 'Add Mode' Button. I then add a note (any note). It is 'blue'. So far so good. Then I press the plus or minus key on my keyboard. I expect the note to move up or down. It doesn't. Come back to me on this. I am obviously omitting something