Main verbs and auxiliary verbs are not as difficult as u think,you only have to read and look at the difference between them and how they work in a senctence.

auxiliary verbs:
be (am,is, are)
have/has/had
do/does

For example
Peter drives a car (drives is the main verb,theres not other verb in that sentence)

Peter is driving a car (is, is the auxiliary verb,as is suports the main verb(driving) )

Does Peter drive a car? (Does is the aux verb,its supporting the main verb (drive) to form a question)

and its exactly like that with the auxiliary verb Have.

I hope that helps u and dont give up any help u need ill be here and like grammar i already finished them and im still doing the 50 hrs online

I'm having a lot of trouble with this question as well. It's got me really frustrated and I'm down to my final attempt :-/ If anybody could help me out it would be very much appreciated! The single line of explanation you get on the page isn't too helpful.