Go onto a game with hdr. For example forza. Go somewhere where there's nice scenery or someplace you think the HDR should really kick in. Then take a picture with your phone of the screen. Not a screenshot, but with your phone. Then take a picture of your settings, in case you want to go back after changing them.
Then start messing around with the settings yourself. Turn the different settings up and down, to give however good of a picture you desire. I personally went with a little bit of extra color. I personally love it and it looks fantastic.
It can be difficult to tell some settings apart, but maybe try and change the scenery (for example instead of parking my car in the sunlight, I'll park it near some trees in the snow). Experiment. Eventually, and hopefully, you'll find some setting that works for you.