The same screen opens that you saw at the end of the tutorial on creating a match

The six entrants were automatically registered by the wizard when I created the match and elected to register all 'regular' shooters.

Now I want to register two shooters who are not designated as 'regular'.  That's why I made sure the check box was cleared before opening the shooter registration procedure.

 

Click Register a Shooter.

(You can also press the Insert button on your keyboard, or right-click the white area and select Register a Shooter.)