If I remember right the water supply has to be active to the unit itself. the little hose going to the brine tank has to be installed as well. You fill the brine tank partly up with salt...usually there is a fill line, and you need to make sure you have a drain because during the charging process water flows out of the little white hose barb. if you have the unit installed make sure to block off the outlet so water cant go through the unit into the machine or flow freely. Shift the lever on the front to the appropriate position (I cant actually read the positions available the picture is blurry).
The brine tank should drain as the charging cycle starts, this runs salt into the unit. Then the rest of the charging cycle is simply to rinse the brine out of the softener itself. good luck, let me know if it works out