Do you prefer to use a large hard disk or several different partitions ? You can answer this question in the « Help with setting up storage space » dialog box. The option already selected (that of the hard disk) is, in general, the one that we recommend for your Ubuntu server.
In the next window, the wizard displays a summary of your file system. If you see several partitions there even though you have not opted for this option, don’t worry: Ubuntu automatically sets aside small partitions of your hard disk for them. system files the most important and your boot loader.