The first step is to sort your different types of fabric by color. It does look a little bit nicer if the shades are grouped together.
I try to find pieces that are similar in size. Then line them up, right sides to right sides with a shared edge. Once you have two pieces lined up, you can move on to piecing them together.
You chain-piece them together with the sewing machine. Continue lining up pieces and piecing them together.
The idea is to add to your original crumb and just keep adding to it and getting bigger and bigger, working to create one bigger square shape. This will turn into your one-color crumb quilt block.
Each time I add a crumb to another piece, I take them to my wool pressing mat and press the seams with my iron to one side. This just helps keep everything flat and easier to work with.