Re-doing individual configurations in "Initial Setup"

At the outset let me apologise if I am in the incorrect forum. I am both a newcomer to quad-copter flying and also to this forum so as you can see I have a steep learning curve ahead.

I am using Mission Planner 1.3.33 build 1.1.5820.11240

I have a newly acquired CX-20 (Quanum Nova) and after battling to get it flying properly in the first instance searching the Internet soon put me onto Mission Planner. Unhappily in the first tries I collided with a tree and damaged the upper shell and lost a propelled nut. I have repaired the shell satisfactorily and I will probably be able to use the 'copter until a replacement shell arrives.

In the interim I have used MP to set the 'copter up in readiness and although I passed through all 16 steps I am not sure that I have set the compass properly. I would also like to reduce the take-off speed. Previously the only way I could get into the air was to give it full throttle otherwise it just tipped over on it’s side.

My question therefore is “can I redo individual steps of the setup procedure” or do I have to start again? In the same vein can I reduce “take off” speed

If this is possible can you describe the steps I should follow please?