That's a soldering iron. You use it to solder. :D Thank you for telling me that :D
Then you really should learn some basics in electricity and electronic before playing with it because you risk to seriously injure your keyboards, your computer and yourself. Would you open the hood of your car ...
I don't even know how to use these.
This is the first time I do the electric thing and it is some how 50% successful
BTW, what is this thing call in English ? http://d2.violet.vn/uploads/resources/183/mohan.jpg