Do you mean the Grades Tool itself? You also have the ability to have Canvas calculate a weighted grade using assignment groups:
Does this help answer your question?
Are you talking about setting it up so the system can DROP scores of assignments? For those settings please look at the below guide.
If you are looking for different group weights or creating assignments groups those would be in the above reply.
If you are looking to create and implement a Grading Scheme How do I enable a grading scheme for a course? check this one out.