How to install a forked version of gitlab using cloud native method (helm chart)

My use case is that, I have a forked version of gitlab hosted on which has so modification. This repo constantly merging/rebasing from upstream (gitlab-org/gitlab). How can I install/upgrade this forked version using cloud native method (helm chart)?

You need to build your own images and use that images in the Helm Chart values.yaml

can I fork any existing Helm Chart values.yaml that the official gitlab is maintaining?