git clone git@github.com:YOUR-USERNAME/YOUR-FORKED-REPO.git
cd into/cloned/fork-repo
git remote add upstream git://github.com/ORIGINAL-DEV-USERNAME/REPO-YOU-FORKED-FROM.git
git fetch upstream
There are two main modes to run the Let's Encrypt client (called Certbot):
Webroot is better because it doesn't need to replace Nginx (to bind to port 80).
In the following, we're setting up mydomain.com.
HTML is served from /var/www/mydomain, and challenges are served from /var/www/letsencrypt.