- Head over to Releases
- Download the newest one (make sure to download the zip that starts with "CustomBanners")
- Unzip the downloaded file in your Beat Saber directory
- Use the template in
Beat Saber\UserData\CustomBanners\Images\Template.png
as a guide for your own image - Save it as a .png in
Beat Saber\UserData\CustomBanners\Images\
Notice:
- when using colored imags turn "Glow" and "Tint" off (in-game in Custom Banners settings)