docs: add installation.md and link from README, index and release

- Create docs/installation.md with full Install with Kernel Flasher
  guide: prerequisites, KMI/SPL selection, steps, supported apps
  (Kernel Flasher / PixelFlasher), post-flash and troubleshooting.
- README: keep concise Install with Kernel Flasher section but link to
  full guide.
- docs/index.md: add Installation entry linking to installation.md
- Release notes renderer (both heredocs): link Features to
  docs/index.md via absolute URLs and add Full guide link to
  installation.md in install section.

.github/workflows/main.yml

@@ -1301,7 +1301,8 @@ jobs:
                 "1. **Download the AnyKernel3 ZIP.** If you don\'t know which file to download, carefully read the description of KMI and Security patch level in this document.\n"
                 "2. **Open the Kernel Flasher app**, grant necessary root permissions, and use the provided AnyKernel3 ZIP to flash.\n\n"
                 "This requires the [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher) app to have root permissions. "
-                "Other apps that can be used include [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher) and [PixelFlasher](https://github.com/badabing2005/PixelFlasher).\n"
+                "Other apps that can be used include [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher) and [PixelFlasher](https://github.com/badabing2005/PixelFlasher). "
+                "Full guide: [docs/installation.md](https://github.com/WildKernels/GKI_KernelSU_SUSFS/blob/dev/docs/installation.md)\n"
             )
 
         def render():
@@ -1574,7 +1575,8 @@ jobs:
                   "1. **Download the AnyKernel3 ZIP.** If you don\'t know which file to download, carefully read the description of KMI and Security patch level in this document.\n"
                   "2. **Open the Kernel Flasher app**, grant necessary root permissions, and use the provided AnyKernel3 ZIP to flash.\n\n"
                   "This requires the [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher) app to have root permissions. "
-                  "Other apps that can be used include [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher) and [PixelFlasher](https://github.com/badabing2005/PixelFlasher).\n"
+                  "Other apps that can be used include [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher) and [PixelFlasher](https://github.com/badabing2005/PixelFlasher). "
+                  "Full guide: [docs/installation.md](https://github.com/WildKernels/GKI_KernelSU_SUSFS/blob/dev/docs/installation.md)\n"
               )
 
           def render():

README.md

@@ -42,7 +42,7 @@ By flashing this kernel, **YOU** are choosing to make these modifications. If so
 ## 📲 Install with Kernel Flasher
 
 > [!NOTE]
-> This method is more convenient when upgrading KernelSU and can be done without a computer. Make a backup first.
+> This method is more convenient when upgrading KernelSU and can be done without a computer. Make a backup first. See full guide: **[Installation Guide](docs/installation.md)**.
 
 **Steps:**
 

docs/index.md

@@ -64,4 +64,6 @@ Per-feature documentation for the GKI2 kernels built from this repository.
 
 ---
 
+**Installation** — see [Installation Guide](installation.md) for flashing instructions (Kernel Flasher, KMI/SPL selection).
+
 **Release Notes** — for build-specific version/commit info, see the [release workflow](https://github.com/WildKernels/GKI_KernelSU_SUSFS/actions/workflows/main.yml) or the releases page.

docs/installation.md

@@ -0,0 +1,56 @@
+# Installation
+
+> [!CAUTION]
+> Flashing a kernel can brick your device and will void your warranty. Make a full backup (boot partition at minimum) before proceeding. You are responsible for your device.
+
+> [!NOTE]
+> This method is more convenient when upgrading KernelSU and can be done without a computer.
+
+## Prerequisites
+
+- Device with unlocked bootloader running a supported GKI kernel (see KMI below)
+- Root access already granted to the flashing app (for upgrades) or a working method to flash initially (fastboot / custom recovery)
+- Battery >50%
+
+## Choosing the correct AnyKernel3 ZIP
+
+Each release artifact is named by **KMI (Kernel Module Interface)** and **Security Patch Level (SPL)**.
+
+- **KMI** — e.g. `android12-5.10`, `android13-5.10`, `android13-5.15`, `android14-5.15`, `android14-6.1`, `android15-6.6`, `android16-6.12`. Must match your device's current kernel version. Check with `uname -r` or in Settings → About phone → Kernel version.
+- **SPL** — monthly security patch string in the filename. Pick the build closest to your current SPL; newer SPL is generally backwards compatible but read the release notes for breaking changes.
+
+If you don't know which file to download, carefully read the description of KMI and Security patch level in the release notes before downloading.
+
+## Install with Kernel Flasher (recommended)
+
+This requires the flashing app to have root permissions. On first install from stock (no root yet), flash via recovery or fastboot instead, then use this method for subsequent upgrades.
+
+### Steps
+
+1. **Download the AnyKernel3 ZIP** for your KMI/SPL from the latest [Releases](https://github.com/WildKernels/GKI_KernelSU_SUSFS/releases) page.
+2. **Open the Kernel Flasher app**, grant necessary root permissions when prompted.
+3. **Select the AnyKernel3 ZIP** you downloaded and flash. Do not interrupt the process.
+4. **Reboot** when prompted and verify KernelSU manager shows the expected version.
+
+### Supported flashing apps
+
+- [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher) — recommended, actively maintained
+- [PixelFlasher](https://github.com/badabing2005/PixelFlasher) — alternative with advanced options
+
+Both require root to flash a kernel from within Android. For initial installation without root, use fastboot (`fastboot flash boot`) or a custom recovery that can flash AnyKernel3 ZIPs.
+
+## After flashing
+
+- Install / update the matching KernelSU manager APK (see release assets `manager-apk-*`).
+- If using SUSFS, install the SUSFS module via the manager.
+- Verify with `su` or manager app that root is working.
+
+## Troubleshooting
+
+- **Bootloop** — restore your boot backup via fastboot/recovery.
+- **Wrong KMI** — re-flash with the correct KMI variant; KMI mismatch is the most common failure.
+- **Manager shows old version** — ensure you flashed the intended variant and rebooted fully.
+
+---
+
+Related: [Kernel Features Documentation](index.md) · [Releases](https://github.com/WildKernels/GKI_KernelSU_SUSFS/releases) · [Kernel Flasher](https://github.com/fatalcoder524/KernelFlasher)