Working with variables and switches?

To be honest I do not know how to use preconditions, switches, or variables. I'm still pretty new to RPG Maker XP, but still have alot to learn. If anyone can link me, or explain to me how they work it would much appreciated.

BTW how do I create "Messages"? Is it the same as "Text"?

Edit: Also, how do set variables?

Yes Messages r the same as Text.
click on this 4 switches and veriables
http://zelaron.com/forum/showthread.php?t=40088