Do you mean networking between them? There's two ways of networking between containers. One of them is to create a custom network for a set of containers that you want to connect between each other. Then you can access other containers in that network using their name and port number like so
container_name:1234
Note: DNS is disabled in the default network by default so you can't access other containers by their name if using it. You need to create a new network for it to work.
Another way is to group them together with a pod. Then you can access other services in that same pod using localhost like so
localhost:1234
Personally in my current setup I'm using both pods and seperate networks for each of them. The reason is I use traefik and I don't want all of my containers in a single network along with traefik. So I just made a seperate network for each of my pods and give traefik access to that network. As an example here's my komga setup:
I have komga and komf running in a single pod with a network called komga assigned to the pod. So now I can communicate between komga and komf using localhost. I also added traefik to the komga network so that I can reverse proxy my komga instance.
Any reason why you use compose and not quadlets?