You can not use the wizard for this. The wizard assumes that weather stations are already present.
To add stations, go to Parameters -> Station Data - GSOD.
Then Click on Import Station Header info.
Wetbud will download the latest header info from the internet.
Select the station(s) that you want and click "Create New Station Record"
Once you create the stations in your study area, you need to populate the stations with data.
Exit these forms back to the main menu and access Parameters - Precipitation Data (GSOD)
Download the available precipitation data.
A lot of times you need to mix and match stations to get a complete set. This is the most time consuming part.
Once your precip data have been downloaded (and checked), you need to download the appropriate WETS data (Station Data -> Wets)
There are more steps that follow before you can actually setup and run a project.
You may consult the full manual for details.
Will be happy to provide more info once you have downloaded all required data.
Note: if the Sussex County data are not available through GSOD, then you may need to manually download them and add them to a station. If that is the case, let us know and we will provide more info