Not a stupid question and indeed there is!!!
Download the attached WinZip Archive, extract, run the extracted .EXE setup / installation file, and you're done.
Will work for any instrument really. Just make sure that you're 100% familiar with your tick sizes, tick values, and commissions payable (if any). Bear in mind that commissions, if payable, are (normally) payable when opening a position as well as when closing a position so the commissions input are automatically multiplied by two (note that I'm not referring to the spread here i.e. the spread will be compensated for by the difference between your entry price and your stop / stop and reverse price assuming of course that you input the correct prices i.e. bid / buy / ask / sell depending on the direction of your trade).
TLCFDPCalcSetupv4.0.zip (688 KB)