Idiots guide to grow lights

They won't work on an external timer unfortunately. There is an integral timer which gives 3/6/12 hrs but I turn it on about 8.30am when we get up and off at about 11.30 when we go to bed say 15rs +/- 1hr.
We shall see whether it serves the purpose.
All growlights need a surround of Hobgoblin, didn't you know this??