Squarespace domain pointing to Public IP

I'm trying to point my squarespace domain I purchased to my Public IP.

I am using Ubuntu Server

I have a localhost Next.js app on port 3000. I port forwarded that port and I can access it on a different computer/different network via using my public IP.

Do I need to change my /etc/hosts file to involve the domain name in it attached to my public IP/ipv4

I'm brand new on using domains and networking so your patience is appreciated.

Any advice or points in the right direction would be appreciated.

I pointed to my domain to my public IP via DNS A with @ in the host field.

I'd imagine if I do www.example.com:3000 it'd come to my webserver but it doesn't.

I thought about trying to set up express.js on my next.js app but not entirely sure if id benefit.