Amend missing description and add manual images.

[bluetata]

I am an employee of Deloitte China Chongqing site. I attended the workshop on Saturday(05/07/2022).
In the workshop, we found there were some minor inaccuracy points in the manual.

• Amend retired input option description of Multi AZ(in the past: it's a check box, now: it's a dropdown list)
• Add some reference images that how to create the target endpoint.