Don't apologize… research! You start learning about complex profiles by using the reference manual once someone points you to a phrase that you don't understand.
But there's tricks to making a useful complex profile in this situation:
1: the fill material should be glass - this defines the edges of the cutting wall. Also, the applied material [in the wall tool] should also be glass.
2: you'll be drawing the opening ACROSS the direction of the receiving wall - just like you'd cut out an opening.
3: Wall priorities can mess up this automatic trim. Always have the opening shape's priority override the receiving shape.
In summary, learn how to make complex profiles. MAke the window shape a fill. Place the fill in the complex profile editing window, save and then use it to draw a wall crossing the receiving wall. See my illustration.
Dwight Atkinson