[Configuration Help] Not clear on how to add HTTPS

[sTiKyt]

I have my Firefly III server running fine, after precisely following steps described in "Using Docker Compose" section at
https://docs.firefly-iii.org/firefly-iii/installation/docker/

I can access my firefly instance by going to specific IP through web browser

But how do i attach it to something like subdomain.domain.com?

I've tried figuring it out online, but after many steps, and some outdated guide i only managed to mess up and break my instance, had to delete it and reinstall everything again.

Is there any clear step-by-step instruction on how to attach this instance to a subdomain, add SSL, etc.?

Could someone explain it to me please?

[JC5]

Do you already have a domain or a subdomain available?

[sTiKyt]

Sure

[sTiKyt]

So, any way to achieve my requirements?

[JC5]

Sure, where do you want me to begin? I can answer specific questions but I'm not a tech support oracle.