You are receiving training so I expect you are being told how to do it. What you need is to develop trigger control. Dry firing is a good way to gain familiarity with the gun/trigger and ultimately trigger control. The more practice you get with the trigger the better.
Remove the magazine and make certain the chamber is empty. Triple check to insure it is empty. Remove all ammunition from the room you are going to dry fire in. Then simply pull the slide back to cock it then aim at a target and practice your squeeze re cock and do it again many times. After you feel a bit more confident than you are now try laying a penny across the slide or sight and try not to have it fall off when you fire (dry/no ammo) keep that up till you can squeeze it off without disturbing the aim or losing the penny.
Good luck and have fun in the process.