I always see people mousing over a function in mathematica and this bringing up a small window from the documentation showing the arguments the function accepts, etc. On mine I have the "i" and clicking on this opens the documentation (I do have the documentation downloaded now, so it opens the documentation as an app not in the web browser) but mousing over it doesn't show anything.
What version are you using?
Type Plot followed by Tab or [ and you should see
Plot
[
Click on the downward chevrons
