As this is Alpha built so there are lots of bugs are there in it.Some of them are given below.
So here are bug list present in Cm 13 rom of Note 4.We already shared CM 13 roms for many other Samsung devices you can also check them out.
1.Finger print scanner is not working.
2.Some battery draining issue.
3.NFC not working.
4.Probably a lot more for updated bug list visit XDA thread
So If you fine with the bugs given above then you can try cm 13 rom for Note 4 by following below steps on How to install Cm13 rom in Samsung Galaxy Note 4.
1.Your device must be rooted
2.Any custom recovery is required (TWRP/CWM).
3.Make backup of current Rom before flashing Cm13 rom.
4.Make sure you are on COI3 bootloader and modem
#How To Install CM13 Rom on Galaxy Note 4
Copy it in your in your device.
2.Now place the Cyanogenmod 13 rom and gapps 6.0 zip file in sd card.
4.Then flash blobs.zip file and gapps from recovery in it.
5.Now Clear cache and Clear Data.(Full Wipe Preferred)
6.Reboot your device.Done! you just flash cyanogenmod 13 rom in your Galaxy Note 4.Enjoy Android Marshmallow 6.0.
See also :Download Cyanogenmod 13 Rom for Galaxy Note 4