"Next, take a flint knife and make a long incision down the left side of the abdomen - actually, it's best to have a friend do this, since the person who cuts open the body must then be pelted with stones to atone for the profanation."
Key Idea core parts: subject - knife, verb - make, object - abdomen
Subordinate conjunction: since
subject - person, verb - cuts, object - body
Would 'profanation' be the object of the verb, 'to atone'?
passage from "How to Mummify a Pharaoh" by Adam Goodheart
There's five clauses in your selection, so if you're trying to identify all the parts, you need to do it five times:
[You] (subject); take (verb); knife(direct object)
[You] (subject); make (verb); incision (direct object)
etc.
No, 'profanation' is not the object of 'atone'. 'Atone' is intransitive.
But I'm not sure what you are trying to do. If you are attempting to parse sentences, I'd suggest you try with simple ones first.