Directadmin is a very great control panel. When we installed Directadmin, I needed to install SSL to the hostname. So, this is just a short article you can get a quick idea.
Open putty and access by using your IP and credentials.
Then use the following command (Replace the hostname first) and run it.
/usr/local/directadmin/scripts/letsencrypt.sh request_single your.hostname.com 4096
So, I hope you could make it successful. Please let me know if you got any issues. Thanks for reading the article.