Insert - Via
The term "via" commonly refers to a connection from metal on the substrate surface to the ground plate beneath the substrate. However, as used in Sonnet, a via can be used to connect metalization between any substrate or dielectric layer, not just bottom layer to ground.
Use Insert - Add Via when you wish to add a via to your circuit. You select what type of polygon(s) you wish to add from the Add Via menu.
Insert - Add Via - Draw Via Rectangle
Insert - Add Via - Draw Via Polygon
Insert - Add Via - Via Rectangle
Insert - Add Via - Circular Via
Insert - Add Via - Up One Level
Insert - Add Via - Down One Level
Insert - Add Via - Down to Ground
Tool Bar Button: 
Click on the 
to open this menu in the Insert tool bar.