My problem is I press the button and the helo immediately tries to kill me.
That usually happens when you fight the damper. What happens when you don't work the damper the way it is intended to is that it fights against your control inputs trying to keep some attitude, then when you trim its input suddenly vanishes and you get (seemingly) uncommanded cyclic inputs.
What worked best for me is to always let the platform stabilize before releasing the trim button. If your attitude is changing and you release the rim, the AP will try to keep the attitude the platform had when you released. So suppose you want to enter a turn:
Press and hold trim, apply cyclic input to enter the turn, only when your bank angle has stabilized, release the trim button. You can trim for a turn too, that is not a problem. Above a certain turn rate, the AP will try to maintain that turn rate. When you come out of the turn, again first press and hold trim, apply cyclic to negate the bank, when you're stable at 0 bank (and no turn rate, because of what i said before) release the trim.
The trick is to make the AP work for you, not against you. Once you understand how the AP works, it becomes a remarkably stable platform. Alternatively you could fly in flight director mode (i think that's what it is called) with only dampers and no AP stabilization, but IMHO you are trading away a lot of hands free goodness.