In the top right corner of your screen, there should be a little bar. Here is where you can add different gadgets.
http://i33.tinypic.com/28w2lj6.png
Once you have added a gadget, you can make changes to it by hovering your mouse over the gadget. A little bar should appear to the side of the gadget.
To get rid of the gadget, click on the "X" on the bar.
To make changes to the gadget, click on the spanner icon.
http://i33.tinypic.com/103ym34.jpg
Quite simple really.
You'll get used to it in no time. =]