GUIde and gadgets

Okay, i saw on the b+ beginners manual thing something about functions, which was not explainedd 2 me. Can someone tell me wat are theses gadget things and also wat GUIde, the thing on the home page is and does?
Please, I really want to know this stuff.

A function is a useful piece of code that you can call again and again from different places with a single command.

Gadgets are all the useful buttons, sliders, tabs, and other elements that make up a user interface. Windows is full of gadgets.

GUIde is a tool for BlitzPlus to make it easy to design a user interface. Instead of guessing what position/size will look best for a particular gadget, you can move them around until you are happy and then output the code that makes them.

GUIde forum here: http://playerfactory.proboards25.com