Remote Access through Subdomain

So I have my nextcloud server up and running in my LAN but I want to access it from outside. I am not really familiar with how to do it and after read a lot of articles I couldn’t find something that is specific to nextcloud.

I understand this involves using a DDNS to combat the dynamic ip given by the ISP but I am confused how to link that and the ports I forwarded (80, 443, 4443) and the domain name to my server ip.

The domain I have is from google where I currently have my website and am planning to add this as
Any help would be appreciated.

Nextcloud version (eg, 13.0.1):
Operating system and version (eg, Ubuntu 18.04):
Apache or nginx version (eg, Apache 2.4.29):
PHP version (eg, 7.1):