It is covered in the links I've already provided you.
Here's a screenshot of the API call format:
If you're wanting a simple dump of the rules in a viewable format, you need the following two clish commands:
- show access-rules type incoming-internal-and-vpn
- show access-rules type outgoing
For full details, then you need the output of "show configuration" which will give you everything (including the router and access policy configuration).
The actual commands sent in the API call must be base64 encoded, as described in the documentation.