Worth a shot! Check out the Qiime2 docker install docs and this tutorial. 
The Remote Explorer uses SSH, so try the SSH client tab shown on that Amazon AWS screenshot.
To start, let's see if we can get a basic SSH session running between your computer and your EC2 instance.
That's the right command! See if that SSH client tab gives other advice about connecting to your instance.
Thanks for sticking with it while we figure this out. I apologize for the scatter-shot approach. There's a bunch of ways to set up this software and connect to remote machines.
You mentioned that you were new to Qiime2, but also you are using AWS and Docker which is well beyond many traditional microbiologists. What kinds of unix software have you used before? Maybe we can use that as a starting point for qiime2.