Torque 3D Gui Help

So lets say I start my game, how to I open the gui (f10?) and add a button on the screen (example top right corner), a button with my own image to be in the game, that way I can use that "button" in the game to be able to click on it, and I want to add a command to build a building,

so when I click on the button on the game screen the building should show up in a shader and if you click on the terrain the building will be placed there, how do i do that ?