How do you make your own museli?

I tried eating honey porridge uncooked with milk and rice krispies it tasted disgusting. It was just so sugary so i plead with someone to give me a good, easy, cheap way to make muesli. So far I can Only find porridge oats. I am confused where do you buy wheat bran/oat bran from and all the other unique ingredients you find in muesli. I have looked in Tesco, Sainsburys that's where I shop but can't find anything!!!