Sorry for the swearing. It's just I've spent 8 hours trying to set this up with no luck. Right now I just engaged gradlew and now I'm stuck at Building 56% > :decompileMc. I errored out twice, so I did what was suggest. Boost the ram.. and now it's stuck at 56%. I don't know if that means it successful and my computer is really slow or it froze. Either way, I went to .gradle and put "org.gradle.jvmargs=-Xmx2G" in the gradle text document I made using notepad.. and titled it. gradle.properties.. and inserted "org.gradle.jvmargs=-Xmx2G" as well.
:decompileMc FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':decompileMc'.
> GC overhead limit exceeded