Via the field "Scale" you can set a scale for a printout or a print view (see image below). To set a scale for a printout or a print view, start by setting a paper size and a paper orientation for it. This is so that you will have the right size frame within which you have to fit the model after selecting a scale. For more information on how to set a scale on a printout, go to section 9.16.2. then read step 10 in the section "Create a printout without a print view". For more information on how to set a scale for a print view, see step 5 in section 9.16.3.