How do you tear apart the air condition unit. on 1998 GMC Jimmy

The clutch on my air conditioning unit wont go in and out so I went and got another one and it still won't go in or out. Can you tell me what is wrong or how to tear my AC unit apart to get it to work.It use to work the it stopped about a week after I got it and I haven't had AC in like 6 weeks now and I have 2 babies so I would like to have air cause of them.

Asked by for the 1998 GMC Jimmy