I wish to apply the SWAT tool in modeling the streamflow of a particular river basin, so I need to master the step-by-step procedure for this tool. Do you know anyone who can assist? Regards.
Everything is provided in the manual (ArcSWAT), at first try to run the example file which is provided in the model. During that process you will get idea or knowledge about the processes and the parameters used in the model for simulating the hydrology of a watershed. You will also come across with the data required and the format of the data used by model, which is the key to run any hydrologic model.
As the others said there are training clips in Youtube avaialbe and the model basic informations in the SWAT User Manual. Moreover, The SWAT Tutorial can help you much more.
The tutorial is a good starting point. If you find any issue in doing so the ARCSWAT user forum can be a good resource. Just drop your questions there, or your questions may have already been asked by other users and the answers may already be there. There are many helpful SWAT users out there who can answer your question promptly. http://biomath.ugent.be/~ann/ArcSWAT_Nzoia.pdf
In my opinion when you bulid some watershed on the ArcSWAT, calibration and verification is very importnat. So you need to read many papers as to estimating parameters.