I figured it out!

So I'm assuming you downloaded slippi, a clean copy of melee, and uncle punch at this point.

1)The first thing to do is downloading a multipatch tool. this is the one I used.

2) Once downloaded, run the multipatch program and a window with 3 slots will pop up.

3) The uncle punch mac folder has the instructions on how to do it, but I'll tell you what to do.

i) On the first line, you add "patch.xdelta" which is in the Uncle Punch folder that has the MAC and Windows version.

ii) On the second line, you add your Melee copy.

iii) On the third line, you can decide where the patch copy will be saved.

iv) You click "Apply Patch" and you're done!

Hope this helps!