Understanding Git Deployment Permission Settings

Thank you for your continuous support.
I'm a beginner who just started studying servers.

The other day, I had a problem with permission with a group of users, and they helped me, but a similar question occurred separately, so I decided to ask you a question again.
It may be a rudimentary question.I'm sorry.

[Prerequisite]
·To build a Git environment, we created a git user
·Creating a remote repository in /var/lib/git/test.git
"·FTP was done with the ""admin"" account until the Git environment was prepared

[What I want to do]
·I would like to deploy the above remote repository to the public area /var/www/html/test/
·At the same time, I want to be able to FTP to the public area

[Process]
You can push locally to the remote repository and clone from the remote repository to the public area without any problems.
The description in /var/lib/git/test.git/hooks/post-receive is

#!/bin/sh
cd/var/www/html/test
git -- git-dir=.git pull
echo test>/tmp/test.log

So, I put the last echo in for checking operation, but since it is output, I think post-receive is running...

】Question br
Is it difficult to say both FTP and Git deployment?
I've tried various user group settings, chown, chmod, etc., but I'm having a hard time because it doesn't work out the way I want.
FTP was done by adding the git user to the admin user (usermod-aGadmingit), setting the folder in the public area to 775, setting the file to 664 and setting the owner to git:admin, but it doesn't seem to be deployed.

What kind of settings should I set for successful deployment?
I'm really sorry that I didn't understand the authorities properly.