These instructions are not great. However with a little trouble shooting, here is what I found. The adjustment knob what the most confusing. It has a graphics of less to more. Basically, when turning to the less, or counter clockwise, you will be asking to come on when it's darker outside. If you turn it to the more side or clockwise, it will come on when it's lighter outside. So, think of the graphics as more is more light outside to come on, and the less side is less light to come on. 1/4 turn seemed to adjust my on time by 10 minutes. So set it one day and see if you can watch for the on time or lightness outside. If you want it to come on at a darker setting, turn counter clockwise by 1/4 turn and then watch the next day. I could not get it to reset the same day, so I had to do the adjustment daily until I got it the way I want it. Patience people. Otherwise it's working perfectly.