After you select the model, you have to decide which pattern will be applied to the part of the model you select. To be able to apply the selection, you can move the part of the pattern using mouse and selected part will be marked as "green" color. When you select the part, patterns that you can choose will be viewed on the left side of the screen. When pattern is selected, it will ve applied on the part of the model automatically. If the patterns are categorized, you can choose them from the "Category" menu where patterns are listed.