Since it doesn’t seem like your operating system has a packaged version of Certbot, you should use our certbot-auto script to get a copy:
wget https://dl.eff.org/certbot-auto chmod a+x certbot-auto
certbot-auto accepts the same flags as certbot; it installs all of its own dependencies and updates the client code automatically.
Certbot’s DNS plugins which can be used to automate obtaining a wildcard certificate from Let’s Encrypt’s ACMEv2 server are not available for your OS yet. This should change soon but if you don’t want to wait, you can use these plugins now by running Certbot in Docker instead of using the instructions on this page.