I don't use those sorts of tools much, but the ImageJ documentation is fairly thorough at he above documentation site.
A couple of notes: Those ROIs will not be saved with the FITS image. You will need to output a .png or .jpeg image to present those later. To use some of the mouse moves, you will need to exit "Astronomy Mode" by clicking on a toobar icon to the left of
the the one circled here:
Be sure you click on the circled icon again when you want to re-enter normal AIJ operation mode.