When you are editing your circuit in the project editor, you add ports by selecting the menu command Insert - Port or by clicking on the Port button in the Insert tool bar. Holding down the shift key when you select the command allows you to add multiple ports. By default, the software automatically determines the type of port based on the location in the circuit; you may also choose the type of port to add. For more details about adding a port, please see Insert - Port.
After a port is added to the circuit, you may change the port type and port properties by double-clicking on the port, or selecting the port, then selecting the menu command Object - Port Properties, to open the Port Properties dialog box.