In this ArcGIS Pro tutorial, I show you the practical workflow I use to create Flow Direction and Flow Accumulation from a DEM. We start from the basics—making sure your DEM is properly prepared—then I walk you through sink filling (Fill) so your surface runoff model is not broken by pits and spurious depressions. After that, I run the Flow Direction tool to generate the flow grid, and I follow it up with Flow Accumulation so you can clearly see where water concentrates across the terrain. Along the way, I share the key things that usually make or break the result: cell size choice, handling NoData properly, and why preprocessing the DEM matters before you interpret drainage patterns or extract streams. By the end, you’ll have both rasters ready for watershed analysis, drainage network mapping, stream thresholding, and even as inputs for flood or runoff modeling. If you’re a GIS student, hydrology person, or environmental analyst, this is the exact step-by-step sequence you can apply fast inside ArcGIS Pro.