To insert Time-Series Data, you have to select Time-Series Data Manager from the Components button.

In HEC-HMS, there are several basin modeling methods available, depending on the level of detail, available data and purpose of the simulation.

The basin model consists of multiple elements representing hydrologic features. These can be added by right-clicking on the Basin Model Map and selecting Add Element. The key elements include:

In HEC-HMS, when you click on GIS in the menu bar and then select Preprocessing Sinks, you perform a GIS operation to identify and handle sinks in the watershed model.Once performed this operation, it is not possible do undo it. Therefore, before doing it, be careful to have your DEM file correctly saved in your folder or create a copy of it.

https://spatialreference.org/This website allows to download the .prj file to set the coordinate system of your HEC-RAS and HEC-HMS files.

The first steps for the beginning of an HEC-HMS projects are: 1) Create a New Project, giving a Name, a Description and a folder location.File > New > Create New Project