[Repost from wrong forum page] Noob wanting to create shortcut panel. Help appreciated

Hey all, hope you're all great XD

I'm gonna write this in short, punchy sentences as I have a habit to rabbit on, lol.

First time in this particular forum. Only just this week started creating editor tools and scripts.

Watched the Unity youtube vid on the technology behind the Heretic movie (would love to see a full feature length movie by this team!), and noticed that they had a cool little panel below the main inspector that allowed them to quickly find and select important objects. (See Pic Below)


This is a cool little tool.

I have 2 questions:
1) I've been totally lost with regards to editor programming - where should I start? Any good guides/references?
2) What would I need to use to replicate this simple tool (have a button for important scene assets, click said button and it highlights/selects said asset in the scene)

As always, I appreciate all help and replies.

Mike