SWAT projects created by ArcSWAT and QSWAT shares the same structure. In this video, I talked about the structure and how the SWAT Viewer use the information to run the model and show the model result on a map. If you are not using ArcSWAT or QSWAT to create your model, you still could use the SWAT Viewer as long as you have the model input files saved in (scenarios -> scenario name-> txtinout) folder and the reach and subbasin shapefiles saved in (watershed -> shapes) folder.