You don't need to prepare any written lesson plans or reports prior to your Q-Comp observation.

An observation must be with students and can be for any length of time, based on what you want observed. Some questions you might consider:

What area of my teaching do I want to improve on?

Which student(s) do I have the most concern?

What part of my lesson am I most concerned about?

What portion of the day would I like an extra set of eyes on?

You might also consider Charlotte Danielson first and what areas you would like to focus on for continued improvement.