Since using qemu means using a virtual computer, the steps to set up the virtual machine are in close analogy with those to set up a real computer. You'll need to decide about CPU, memory, disk, USB devices, network card(s), screen size, etc. Once the <quote>hardware</quote> is decided, you'll have for example to choose how to connect the machine to internet, and/or to install an OS. In the following, we show basic ways of performing those steps. But qemu is much more than this, and it is strongly advised to read the qemu documentation in <filename>/usr/share/doc/qemu-&qemu-version;/qemu-doc.html</filename>.