How I get SSL for my Subdomain and show me other SSL Certificates

Hello together,

I have the following conditions:

• Bought Domain at Namecheap
• Did DNS with AWS
• At AWS is a CNAME to my Domain here at DO (it is a tracking Server/Domain)
• I use a Subdomain at my tracking Tool. The Tracking Tool is hosted on DO. I need a SSL certificate for this Subdomain. So I must install the SSL certificate on my DO Server.

I know that the IT expert at my company has already used this procedure for other subdomains. (He’s no longer with the company, so I can’t ask him)

How do I get to the console of my DO server and with which command can I check whether there are already more SSL certificates for other subdomains? In AWS it is e.g. sudo certbot certificates (I use let’s encrypt there)

Thanks a lot