Custom tool button/gui

I want to make a custom button so if you click it you equip a tool, since im really unexperienced i have no idea how to do it.

By choosing u want your model as a tool u pay the price of defoult tool button. So if u want to make ur model outside of the tool u need to know:

Welding models to the hand
Creating pick up animation and idle
Creating equip button and script it