Those are the mod_md docs that I linked in my first reply and are what I would have offered again, had @MikeMcQ not already repeated it for emphasis. 
The github repo shouldn't be needed as long as you are running Apache 2.4.30 or newer, as it has been included since that version.
Like any module, you will need to enable it and configure it. I put the vhost related elements directly in my vhost configs. I also keep some global configs in /etc/apache/conf-available/md.conf
MDCertificateAgreement accepted
MDContactEmail ssl@example.com
MDPrivateKeys secp384r1 rsa4096
MDStapling On