When I wanted to set this up, the process was confusing I found a post on Reddit that provided more clear instructions for me to use. I've copied it here (and fixed some of the spelling mistakes) so that it's on Lemmy too.
Hi!! Since i used to struggle a lot with the guides available (partially bc of attention span issues) and i had to figure out lots of things myself when i first got into ReVanced, here's a step by step guide for downloading it on non-root devices! :>
Be nice please and excuse any grammar errors since English isn't my first language, if there's anything i missed, let me know!
DISCLAIMER: Never download from (or use) sites that arent apkmirror and/or GitHub. These are the only ones necessary anyway and the other ones are not trustworthy. Also, ReVanced doesn't work for iPhone devices as far as I'm aware (sorry lol). THE STEPS IN THIS GUIDE MIGHT NOT BE NECESSARY FOR EVERYONE BUT THEY WERE FOR ME its okay if you find it a little overboard but i struggle with following tutorials and i struggled with errors that most ppl didn't mention anywhere so i included the fixes that helped me!
Links for the necessary downloads are at the end
Preparations:
Turn off Google Play Protect
Allow unknown downloads for your browser in settings
Disable/uninstall YouTube app
Steps:
Download Vanced microg
Download Revanced Manager
Open your files app and install both
Open ReVanced Manager. Check for the suggested version of YouTube (patcher -> select application, then find YouTube and check for the currently suggested version)
Look up "YouTube apk [suggested version]", find & open apkmirror.com, download the correct one that is NOT a bundle (and pick nodpi) and install it as well
Go back to ReVanced Manager. patcher>select application>YouTube.
Click on selected patches. either use the default ones or you can do some cherry picking on your own. (some patches that i find worth including are at the very end, dont entirely depend on them alone tho)
Once done with patches, ensure that you included "vanced microg support". That one is necessary.
Press done and patch. Once its finished, just install it.
there you go :> ReVanced is ready to be used and you can sign in to your account
Shorter Version:
Download and install Vanced microg, ReVanced Manager and the currently suggested YouTube APK
Open Revanced Manager, select YouTube to patch it
Select the patches you want (must include Vanced microg support)
Let it apply the patches and install once its ready
Repatching ReVanced after an Update
Open and update ReVanced Manager if needed
Check the currently suggested Youtube version and download it, if necessary, from apkmirror.
Delete the old Youtube APK since you wont be using it anymore
Repatch and install
NOTES:
-I don't recommend just applying all patches, especially since you may not want everything they have to offer or they sometimes cause problems for some people. its best to go with default and then check if there's anything you want to change (including or excluding some patches)
-if, for whatever reason, you still encounter errors such as the patching process aborting, the app not opening or something else going wrong,, please make sure you have followed every step correctly and if necessary, go over your patches again. Try starting from the beginning if you cant find other solutions.
-after you have successfully finished everything, feel free to turn Google Play Protect back on or disable downloading from unknown sources for your browser, if you'd like.
the most important patches (imo) to be included:
-vanced microg support (obviously)
-client spoof
-hide ads
-hide watermark
-sponsorblock
-video ads
plus: exclude enable debugging to make ReVanced work more smoothly!
And like i said, don't just rely on them entirely otherwise your YouTube app will probably suck really bad ngl but these are the ones i feel like should be included for sure.
Links:
As for the YouTube APK, you can look up the suggested version and find it on apkmirror (Note:I didn't put the link here because I think it may count as a link to a pirated title, not sure though)
Good Luck!!