Can anyone tell me how tuplets work in a way normal people can understand? Google yields results you have to be a rocket scientist to understand.

I just want to know what you change this to;

http://i46.tinypic.com/208k6q0.jpg

To get a tuplet like the one in the red circle;

http://i45.tinypic.com/2ivyadi.jpg

Any help is greatly appreciated.

Make it:
3 Eighths
in the space of
1 Quarter

Basically, you have this space (which is 1 quarter, for what you wanted it to be).

Then you choose how many notes go in it.

It's a fraction. It's actually quite easy IMO... -__-