I struggled to install it on my own too, but GPT 4 fixed that issue splendidly. I highly recommend you try: create a free account on chat.openai.com if you haven't already (GPT 3.5 is free, GPT 4 costs $20/mo), and then give it a prompt similar to this:
"Help me understand how to install arc. When I try to install in racket it says:
racket: undefined; cannot reference an identifier before its definition >"
