extract the zip file
run the program, the exe (AssetRipper.GUI.Free.exe)
a browser will open to the interface of assetripper
click file and click open file
locate where you put your vrca/vrcw file
select your vrca/vrcw and click open
click export and then click export all files and then click select folder
locate where you want to extract it (MAKE SURE THE DIRECTORY YOU CHOOSE IS AN EMPTY FOLDER OR ELSE IF YOU PICK THE FOLDER THAT HAS LOT OF FILES IT WILL BE DELETED)
once you select an empty folder click export unity project and wait, after a while the file will be exported to the folder you selected.

next step is to download FACS Utilities
github.com/FACS01-01/FACS_Utilities
make a new project in VCC not in Unity Hub! make sure the Vrchat SDK is fully installed on the package list, start up the project, while its loading head over to the folder where you extracted the vrca/vrcw, change the folder called script to .script so that unity doesn't get angry at that... from experience, next move the folder containing the extracted vrca/vrcw to the unity project folder that you have created
example: C:\VRChatProjects(your project folder name)\Assets and paste the folder into the Assets folder, the folder name will not get conflicted so don't worry

after unity has fully loaded drag the .unitypackage of FACS Utilities into the unity, wait for it to load and then press Import, wait for it to finish copying and there should be a new tab on the top called FACS, click it and head over to a tab called Script, and then select fix script, drag the folder where it contain the extracted vrca/vrcw, and press Run Fix! Give it a few moment and when its done, head over to the animation tab, select Fix Animation, Put the avatar prefab in the Animation Roots object selector, the name should be (avatar id here).prefab and press Auto Detect, and then press Run! button, give it a few moment again and then drag the prefab into the Hierarchy, and done! the avatar is fixed, except the shader it will look very bad

if you want to learn more about the tools here is the wiki
https://github.com/FACS01-01/FACS_Utilities/wiki

if you are still confused, i will try to assist, just tag me and i will check it when i have time