check https://forums.oneplus.net/threads/cm12s-installer-mini-edition.302260/
This tool will automaticly install CM12S for you, you dont need to do anything.
Only click 1 button and have ADB installed & USB Debugging on.
And the best thing of all: Its cute, tiny and awesome!
As the problems with my previous OxygenOS installer this one will be tested many and many times before a new build.
ADB:
Click me to go to the link enter at all installation steps enter ‘Y’
Step 1: Go to the settings
Step 2: Click below on About Phone
Step 3: Tap 7 times build number
Step 4: Go back to settings
Step 5: Click on Developer Options
Step 6: Enable USB Debugging
Step 7: Install the ADB Drivers inside the .zip
ADB Driver Installer: https://drive.google.com/file/d/0B0MKgCbUM0itVVFWRC02Q0VBQnc/view
(After installing the ADB Driver’s you probarly dont need to do anything again.)