1. Download ROM, Custom Recovery and GAPPS(if ROM does not have built-in GAPPS also if you want GAPPS) on PC (if not installed, OrangeFox, TWRP, etc. are recommended)
2. Unlock Bootloader
(1. Enable OEM unlock in developer settings
2. Turn off the phone
3. Connect the cable from PC to phone
4. Press volume keys + - before blue screen
5. Long press volume key +
6. Press the volume key +
7. Reboot, complete the initial setup, and check for updates)
3. Flash recovery and reboot to recovery
(1. Reboot into download mode
2. Press the volume key +
3. Unzip recovery.img from zip (if it is zipped).
4. zip recovery to .tar
5. Open ODIN and put recovery.tar (or another name).
6. Download vbmeta.tar (yes, that's the link) and place in BL
7. Remove the auto reboot in ODIN
8. Flash recovery and vbmeta
9. Press volume key and power button before black screen
10. After the black screen appears release the volume key - and the power button and press the volume key + and the power button, release the power button after about 3-4 seconds, hold the volume key + until the recovery mode appears.(Ignore warnings))
4. Format data
5. Reboot into recovery mode via recovery mode
6. Copy ROM and GAPPS(GAPPS if you want) to the phone(or use sideload)
7. Flash the ROM and GAPPS(GAPPS if you want)
8. Enjoy

1. Download ROM, Custom Recovery and GAPPS(if ROM does not have built-in GAPPS also if you want GAPPS) on PC (if not installed, OrangeFox, TWRP, etc. are recommended)
2. Reboot to recovery
3. Format data
4. Reboot into recovery mode via recovery mode
5. Copy ROM and GAPPS(GAPPS if you want) to the phone(or use sideload)
6. Flash the ROM and GAPPS(GAPPS if you want)
7. Enjoy