A general guideline for everyone:
Prerequisites:
1. Unlocked bootloader
2. Working ADB environment
3. Your phone must be encrypted (preferably via pattern+fingerprint)
Preparation (for Windows):
1. Download the custom recovery image (TWRP) of your phone to
computer. Link:
here.
2. Rename the image file to twrp.img
3. Download the weekly ROM to your
phone from OP.
4. Connect your phone to your computer
Installation (for Windows):
1. Use explorer to navigate to the folder where the TWRP image is at.
2. Shift + right-click any empty spaces in the folder and select "Open in terminal" (or Powershell).
3. Reboot your phone into fastboot mode:
4. Replace stock recovery with TWRP recovery:
5. Reboot into TWRP recovery
6. You are now in TWRP recovery. Decrypt data by entering your pattern/pin
7. Change language if needed
7.1 Press the 2nd button from bottom right (= Settings)
7.2 Press the last tab (with "globe" symbol)
7.3 Press your preferred language
7.4 Press back button at bottom left to return to main menu
8. Press "Install" (top left button)
9. Browse to wherever your downloaded the ROM. It is a zip file. Select the zip file.
10. Swipe the arrow to right to confirm Flash
11. Prepare coffee/tea/me and wait for it to finish installation
12. Reboot your phone
13. Done.
Optional for root:
1. Extract stock boot.img from your ROM zip file.
2. Download Magisk Manager apk from official github.
3. Install Magisk via direct install.
4. Copy the new magisk_patched-xxx.img to your computer. Rename it to magisk.img
5. Flash the image
5. Do whatever else you need to do.
Hope it helps.