Google Wave, because of it's rather new concept, architecture and working, a lot of users are confused how to use it?? An IM plus an email platform plus media sharing platform plus social networking and more.. it's just enough to make a non geek freak out!!
So here's what you've to do to add a gadget (it's just a series of clicks):
You can create an entire new wave (it's like a new message taken as a whole) yourself or reply to a wavelet (it is a part of a wave similar to a part of the chat lines while chating with your friends online) another waver. The following shows a wavelet. You can click on the blue rounded-corner rectangle below to reply to a wavelet.
When u do that, you are in 'edit mode', then you'll be able to see the toolbar (blue wavy line in below pic),
then click the 'Add gagdet by URL' tool from the toolbar (encircled in red in above pic). U'll be able to see a pop-up, as below,
Now, add the gadget URL there, it's that simple
Googling for 'Google wave gadgets" will return a lot of useful URL gadgets, or you can try out Google Wave Gadget.
