QEMU is a command-line program that must be run in a terminal. The command line must include the options you want to use with your image file. If you open a terminal and type
at the prompt, you will get a list of options. There is also documentation if you type
and there is html documentation in /usr/share/doc/qemu. QEMU is not a user-friendly program and the documentation is quite geeky, but once you find a command line that works for you the program is easy to use.
Next week I'll work on a HowTo for our forum section and will include sample command lines that you can easily adapt to your own needs.