Hello everyone,

our team is still looking for a Project Management Software that fully satisfies our needs as a Contractor.
That includes being able to track Clients and their Projects, as well as having integrated Time Tracking, Invoicing, Leave Day handling, and more.

We know that OpenProject does not offer all of these out of the box and would like to use OpenProject as a base which we further develop internally.
Now, I looked through the Documentation Page and found a couple of very high level writeups.

My question now would be: Is there any document, video, or similar with an actual project overview, which explains how the inner, more low level structure of the project looks like and works?

For example, if I were to add "Clients" to the project, with backend and frontend parts, basically similar to duplicating something like "Projects", what files, classes and steps are involved and required? And does one have to modify the actual Source Code for this, or is it still adviced and possible to create those systems via Plugins?

We would want to add a lot of systems, as mentioned above, so I would love to ensure that we can read up on how existing features are implemented somewhere. Figuring this out by poking Source Code over and over again would be very time consuming.

Maybe I'm just blind and there is a page in the docs, or a series of files in the repo that explains how everything ties together.
Or a tutorial that explains how to add something like "Projects" but from scratch. If so then I would be very grateful for simply pointing me to those resources.

Thanks in advance!