Here’s how to install the unofficial LineageOS 15.1 running on the latest Android Oreo 8.1 on the Samsung Galaxy Note -4. This video will give you exact steps to follow to flash the custom ROM.
1. You need to be on MM bootloader and modem
2. Download the latest build and gapps
3. Reboot to TWRP recovery
4. Wipe system, dalvik, cache and data (only in new install from another rom)
5. Flash the rom and gapps only in first install ( and magiskmanager only for root)
6. Reboot system
To install custom recovery on your samsung galaxy note-4, follow this video
Download links below:
Download ROM from here
Download Gapps from here
Check out XDA thread over here,.
Make sure you follow the instructions in the video carefully