Whilst there are many options for adding a gimbal for a GoPro action camera to your drone, there are only a handful of gimbal kits for the Mobius camera. This is a 'Quick and easy manual' for building the Banggood 3D printed 2 axis gimbal for the Mobius camera and it covers building the gimbal frame, motors and mount. Part 2 covers adding the electronics and completing the build.
The principles are the same for building many action camera gimbals from kits.
Here's the video menu: 00.08 - What you get in the kit and what else is required; 00.36 - Tools and other bits; 00.48 - Preparing the mount (with a Dremel drill); 01.18 - Attaching the motors to the arms; 01.52 - Building the anti-vibration mount; 02.07 - Fastening it all together.