 Welcome to SwissModel. In this tutorial we will go through all necessary steps to build a model using the SwissModel services. Before we start I'd like to point out two things. First the web page has extensive documentation which you can find in the menu on the top. Question marks on the web page link directly to the help page 2. Secondly we are going to build a model of superoxide dismutase from Drosophila melanogasta which can be found on the example page. Prior knowledge about a protein can be very helpful in modeling. In our case we know its function is to destroy radical byproducts within the cells. Furthermore we know that in its native form the protein is a homodimer with two metal binding sites per subunit one for copper and one for zinc.