Gitlab on a dedicated machine behind the Apache reverse proxy with SSL - how?

I have an Ubuntu server running LXD.

I have an LXD container with Apache (192.168.0.3)
I have an LXD container for Gitlab (192.168.0.5)

Nothing specific about LXD itself, just consider Apache and Gitlab running on different machines with different IPs in the same subnet behind the router with static IP, which is a primary IP where DNS is pointing

I have mutiple sites (subdomains of the single domain) hosted on Apache, I want to add my Gitlab subdomain.

I use Let’s Encrypt for getting certs for Apache sites.

I just need to figure out how to set up Apache site for a Gitlab subdomain and what I need to put into Gitlab config.

Do I need to set up Gitlab without SSL first?
Do I have to copy Let’s Encrypt certs generated inside Apache container into Gitlab container or I need to let Gitlab to get its own certs?