Catalyst Backend Onboarding section

# Description

Create as a check list of what should be installed, checked, trying to be run:
- tooling which should been need to installed (placing some link to tutorials how to install or shell snippets how to do it)
- list of all related repos
etc.

No file, test, or documentation entry point is named in the issue. Start by locating where onboarding content belongs in the repository, then define the backend checklist with installation guidance, checks or commands to run, and links to related repositories; done means the section covers those requested items.

Written by the indexing model from the issue text.