Please I need your help.

I have a vps with debian 10 as the operating system. I have a domain name www.example.com with all the subdomains that I can create. I installed Apache web server. I installed gitlab and I made it point to gitlab.example.com In gitlab, I pushed a web project in the master branch,

I would like to point the subdomain master.example.com to the directory of the master repository so that when I type in my browser master.example.com, I can see the rendering of my web project which is in the master branch . For that, I created the .conf file of the virtual host apache /etc/apache2/sites-available/my-master-branch.conf

My problem is that I don't know the path of the document root where my master branch is located

<VirtualHost *: 80>
    ServerName master.example.com
    DocumentRoot ???
    [...]
</VirtualHost>

I read somewhere that it is in /var/opt/gitlab/git-data/repositories/@hashed but this directory is empty, it seems it's hash for security reasons.

Please what is the operation to do to see my rendering on master.example.com ? Or is there another manipulation to change the directory of my master branch to /var/www/my_projet/.git ?