RobynT.........dendros are non photosynthetic so they don't need light to live.......they need to be fed.
That said, some think you should place it in a shaded area but many people have their dendros out in the open or near the corner were it gets subdued lighting. Doesn't matter because the dendro should open up all day anyways.
Consider feeding the dendro a few times a week and feed it stuff like chopped shrimp, mussels, mysis shrimp, brine, cyclopeez, pellets, flakes, etc.
As for flow, I have mine under medium flow. Very high flow made my dendros close up because they were getting blasted.