Defining automation stitches from fortimanager

Hello,

I got confused trying to define some automation stitches for AWS. 

1. Are fabric connector and automation stitches connected somehow ? For instance is it necessary to have a fabric connector to AWS to be able to use AWS elements in automation stitches ?

2. Is it possible to make automation stitches from the fortimanager ? I am able to declare a fabric connector from the fortimanager but i don't see the option for automation stitches.

2. When using automation stitches, where would the API calls come from ? In the case of an automation stitch using AWS elements : does the fortimanager perform API calls ? Is it the fabric's root fortigate ? Is it the cloud-hosted fortigate ?