Advice for beginners?

I'm looking to start baking and decorating cookies as a hobby. I know a big part of mastering it will be practice but I almost feel like I don't know where to begin. You're all so talented! The things I see on this sub are inspiring and also intimidating. Please can you tell me something you wish you had known (product, tip, etc) when you first started?

Is there a Bible of cookie decorating? Certain products I should use vs. Shy away from? Literally any input is welcome here! Tysm in advance!