Play back - specific staves, set start point
Pressing F5 or Tools: Play, Play will start play back.
If you only want one staff to play back, make the staff active and press Shift+F5 to play the active staff (or Tools: Play, Staff Play).
If you want some staves to play and some not to play, use Tools: Mute List for quick access to setting the staves to mute or not mute. (Quick key - M)
To set where you want play to begin each time:
Select Tools: Options and click on the MIDI tab. Under Play Options, you can select play to start
from insertion point
from current measure
from 1 measure back
from 2 measures back
from 3 measures back