the box is open source (you are allowed to use it as you please), previously found on this github: https://github.com/DrPotatoNet/TheBoxVRC

Make a new Unity Project
import the package
Wait a minute (keep it in the background or something, its an all in one package)
import VRChat SDK
Doubleclick the scene "The Box"

click on VRChat SDK on the menu at the top
select show control panel
go to Builder
click "Build & Publish"
type in "The Box" in the title, fill in description
Go to the Scene, in the Hierachy doubleclick on VRCCam
Right-click VRCCam
Select 3D-Object -> Cube
Drag the "Thumbnail" Material onto the cube you created
With the cube selected in the Hierachy go to the Inspector and set the Transform values as follows:
          X          Y      Z
Position  0          0      1.3333
Rotation  0        180      0
Scale     1.3333     1      1
Make sure "Upload Image" is selected on the Upload Menu
click upload

For the Quest Version:
Go to File -> Build Settings
press on Android
Click on "Switch Platform" and wait a bit
select show control panel
go to Builder
click "Build & Publish"
click upload

video tutorial: https://www.youtube.com/watch?v=PslCK3GxYOc

Unity Hub - https://unity3d.com/get-unity/download or direct download: https://public-cdn.cloud.unity3d.com/hub/prod/UnityHubSetup.exe
Click on "here" in the first Paragraph to get the right Unity version: https://docs.vrchat.com/docs/setting-up-the-sdk
