Usage instructions for newbies

Hi,
this seems like an excellent piece of code, but I am not Linux expert and I have no idea, what your instructions say:
Until this is live on the HUB and documentation is complete, **clone** (**what's clone...how to do it on, for eg. Ubuntu 12.04?**) and then:

docker build --tag easywildcard .
DOMAIN="example.com"
EMAIL="letsencrypt@example.com"
PORT=5053
mkdir -p /tmp/letsencrypt

**Where to put these lines?**

I've checked my install and I have:
# certbot-auto --version
certbot 0.27.1

Populated:
/var/lib/letsencrypt/
/etc/letsencrypt/

But:
/opt/certbot or /opt/letsencrypt do not exist on my server.

Please, could you be so kind and add some instructions for newbies.
thanx!

Review the existing installation instructions and the clone, docker build, environment-variable, and Certbot commands described in the issue. Add beginner-oriented steps for Ubuntu users that explain where each command belongs and how the existing Let's Encrypt paths relate to the setup; the documentation is done when a newcomer can follow it without guessing.

Written by the indexing model from the issue text.