I'm having trouble understanding the instructions I found online about making an intersection with these two components. Can someone help me with this?
They form a subassembly in a larger file, and I'm really just interested in the volume that they share.
Edit 2 I am looking to take these two parts from the subassembly and make a new single part where they intersect.
Yes, they ultimately do need to be an assembly, but if it can be converted temporarily that's fine. It can be saved under a new name first as a file with a multibody if necessary.
The only remaining part should be the intersection of yellow and green. (Although if I think about it carefully, it might be important not to remove the portion of green below the intersection in the final part.) The leftovers can be removed as long as it's in a separate file. I still need the subassembly for other things in the larger assembly I mentioned.