Yellowstone river and Henry's lake

[rookiefisher]

I will be spending some time over the weekend of the 26th of July at Henry's lake and also taking a day to fly fish yellowstone river. It will be my first time. I am from Utah so I don't know what kind of flies are good for the yellowstone or what works on Henry's lake. I have done some research on the internet but would also like to get some input from you locals or at least those that have fished the area before. This trip has been a long time in the making and I don't have but a couple of days so I want to be prepared when I get there. Any help would be much appreciated. Also, any specific areas of either spot that are better than others would be much appreciated. Does anyone know anything about any rivers coming in or going out of Henry's lake that would be good to hit?
Thanks all
[signature]