This Guide will help you how to download and install Unofficial CyanogenMod 13 cm13 custom rom on your Samsung Galaxy Alpha SM-G850W by kyasu and has no bugs.
This is an unofficial CyanogenMod 13.0 build for the SM-G850W which is a Snapdragon variant of Galaxy Alpha and has an unlocked bootloader.
1.You should have Custom recovery installed on your device.
2. Make Backup of your current rom before flashing this Rom via Custom Recovery.
3.Your SM-G850W must be on Stock 5.0.2 before flashing this Rom.
#How to Install TWRP Recovery On Samsung Galaxy Alpha
First download TWRP recovery from HERE and follow below guide
Cm13 Rom - HERE
GAPPS - HERE
I AM NOT RESPONSIBLE FOR ANY DAMAGE CAUSED TO YOUR DEVICE. Do it on your own risk.Follow the instructions properly.
#How to Install Cyanogenmod 13 rom on your Samsung Galaxy Alpha
1.Download CM13 Rom and the appropriate Gapps 6.0
2.Now place the Cyanogenmod 13 rom and gapps 6.0 zip file in sd card .
3.Now reboot to Recovery mode
4.Then flash CM13 android marshmallow rom and gapps
5.Now Clear cache and Clear Data.
6.Reboot your device.Done!
Source - xda