what am I supposed to do on first merge?
Don't shoot on that merge, get in a habit of not doing it, even in the MA. Even if it works once in a while, you'll never improve as a pilot and guys will continue to outfly you. By not putting yourself in a bad position you can start learning about ACMs that will be effective.
Read up on e-management (energy management) a little. You continued cutting your throttle or engine then going into verticle where you would lose the little e you had and stall out. Make sure you understand how the stall buzzer works. Losing all that E, then stalling out, and falling to the ground is not effective ACM.
Someone else mentioned this, but pick a plane and fly it almost exclusively for a few tours. Learn its stall speeds, what speed it will compress, etc, just learn the plane.
