Based on email inquiries and postings to the SWMM LIst Sever (a fantastic resource hosted by CHI, Inc.), I’ve discovered that many SWMM 5 users are unaware of the excellent documentation on SWMM 5 available on the EPA website at https://www.epa.gov/water-research/storm-water-management-model-swmm. It is divided into three volumes: Hydrology, Water Quality, LIDs or SuDs, and Hydraulics. The documentation is fantastically complete, with detailed theory background, process parameters, and fully worked out examples for all of the processes in SWMM5. It is truly an outstanding resource for modelers and modellers all over the world. It would be beneficial for you to read them (if you have not already downloaded the PDF files).