How to install GitLab on CentOS 6 with Plesk?

I have a CentOS 6 server with Plesk installed.

Plesk version: Plesk Onyx 17.5.3 Update #49
CentOS version: CentOS release 6.9 (Final)

In Plesk I’m hosting bunch of websites with different ways. NodeJS, PHP etc. I want to install GitLab here on without breaking entire system. Last time I tried the default install instructions I killed plesk and everything was unusable.

Re-installed entire system, now, how do I do this properly without destroying rest of the world?
Thanks in advance!