I grind the flaked (barley, wheat, oats, etc.) in either the Magic Bullet or foodprocessor. And put in mash. If it's a small amount I just mash like usual.
If it's a lot, like a wit I do with a fair amount of oats and barley, then I have done a adjunct mash at 100F for ten minutes and then take it up to the saach rest temp such as 154F.