Now first lets go over the throttle trim lever.
The throttle trim lever adjusts the rotor head speed with little to no changes in collective(pitch) on the blades.

This is important because when flying in idle up mode, you want to be able to increase or decrease rotor head speed without changing your collective(pitch).

While in idle up mode, and hovering, you want a lower head speed so that the collective is not so sensitive around neutral.

As you change into doing aerobatics, you want a higher head speed so that the collective is more sensitive around neutral. This way you dont have to put in lots of collective control during pitch changes like during rapid flips or rolls.

That's why we have a throttle trim lever.

Now you may not be at the skill level to where you need this, but its still important to set the heli up correctly so that this works.