Problem in installing Let's Encrypt SSL for www and non-www

When I re-install discourse, is my website hostname as www.example.com?

I have installed discourse One-Click Application from DO. Which method are you recommend, One click or Linux command?

Install SSL for your www because that is your canonical

When i installing SSL from below method, I have not entered my domain details, so where i have to add www version of my website address?

However must enable its DNS as well proxy for apex domain

Pls, can you let me more, how to do above step?

Force HTTPS - which option i have to select because there are three option related to https?

  1. Always use HTTPS
  2. HTTP Strict Transport Security (HSTS)
  3. Automatic HTTPS Rewrites