OK I downloaded the mod zip file and in that zip file is a folder called NBAmod and in that folders there is a graphics folder and a setup folder. Take those two folders and copy them to your main DDSPB folder (most likely in C:/Wolverine Studios/DDSPB2019) - when you do that it should give you a message that you are going to overwrite files because they have the same names. ie the graphics folder overwrites the graphics folder installed by default and the setup folder overwrites the setup folder installed by default. Once all those items are replaced they should show up in the game.
To start a career with the mod you start a new league and choose the custom league option. When you are prompted to find a roster file you follow the path for setup/imports and choose the NBAmod.mdb file to use as the roster import. That should let you use this mod as the import and then have all the graphics setup for you