In PaperUI go to Things and press the + icon at the top. Select zwave and then click on “Add Thing Manually”. At this point your only option will be the serial Thing.
You will need to enter the address where the controller resides (/dev/tty* on Linux/Mac or COM* on Windows). On Linux the openhab user will need to have premission to read and write on the device. This is often handled by adding that user to the dialout or tty group.