...that you can use Ctrl-U/Ctrl-L to create an index above or below the currently selected elements?
...that you can import and export MathML files?
...to get the most out of KFormula you need to install the TrueType version of the famous TeX fonts. You can find them in ctan at /tex-archive/fonts/cm/ps-type1/bakoma/. However you don't need to install all of those. Right now the fonts cmbx10, cmex10, cmmi10, cmr10, cmsy10, msam10 and msbm10 are required.
...that you can use the keys ^ and _ to create right upper and lower indices? If you type Ctrl-^ or Ctrl-_ instead, you will get a left index.
...that you can insert any of the many supported symbols by typing its name? Simply press the backslash key, type the symbol's name and press space.
...that you can insert Greek letters very easily by typing the corresponding latin letter and pressing Ctrl-G afterwards?
...that you can insert any number of lines using the Multiline element? By inserting & you can align these lines.