Honestly no clue why the tarp is required, but ya you need those three things.
If I cut off a chunk of meat and put it in my pack, no need for tarp, even if it was to keep the meet or grass clean, the hide should be able to do that, and act as a makeshift sack to carry it back in.
Course realistically really don’t need rope and a tree, just makes it easier, you can butcher a moose on the ground with a pocket knife would just take a long time, and would probably attract predators before one finished.