To get the best support from the community, use the standard install for Production. That sets up the docker container and a DB automatically so you don’t have to worry about that separately.
Yes, this can be deployed on AWS.
I suggest using this approach for the time being until you get really familiar with Discourse and can answer your own questions 
Initially you can set your site to login required (in site settings) to keep it private - there is no “under construction” mode specifically.