Follow these steps to install and use a post processor for Fusion 360.
Make sure you can download and save the post-processor to your computer. The post-processor can be found here.
Open the Post Library from the Manage menu.
Import the post-processor into the desired Library:
Now that you've done this, whenever you are finished making Manufacture operations in Fusion 360 the post process dialog will have a Source option for My Cloud Posts, which allows you to use any post processor you've uploaded to the CAMPosts folder. It may take a moment to appear.
Autodesk has an installation video which can be found Here.