In the upper-right corner of the front panel of the subVI (the one you want to include), right click on the icon and select "show connector"
You can connect inputs and outputs to the regions shown by using the wire tool (click on a square, then on the control you want to connect).
If you need more or less connectors you can adjust the arrangement under "patterns" on the same menu.
There are probably other ways of doing most of this as well.