Edge Substratum is a personalization theme for Android devices that allows you to customize your device's appearance. The theme works with Google stock and custom AOSP basedROMs, but it is not supported by LineageOS, OxygenOS, or Samsung devices running stock firmware. To apply the theme, you need to have the Substratum app from the Play Store and your device must be rooted.

When you open the theme in the Substratum app, you will see a drop-down menu on top of the overlays. You need to choose one depending on your ROM Android version. There are also some overlays with different variants for specific Android versions. To apply the theme, select all the overlays, press the floating action button, and choose Build & Update. Wait until the process is over and reboot your device. Open Substratum again, select all the overlays you previously built, press the floating action button, and choose Enable this time.

This theme works on system-only features and is not fully supported by all ROMs, so it is recommended to read all options carefully and disable auto-updates on apps from the Play Store. If you encounter any issues or want support, you can join the developer's Telegram group.