How do you get rid of the default toolbar, and how can you implement a custom toolbar?

Title says it all. I am not expecting a step by step guide but any help is greatly appreciated. Thank you.

In a local script you could use this:

game.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.Backpack, false)

But exploiters could easily bypass this, so... It's better if you just create a folder inside the player's backpack that holds the tools. This is just one way you could do it, I'm sure there's plenty more ways.

To implement a custom toolbar, you'll need to make one yourself.