You'll need some day old bread, or bread that you have in the freezer that you need to use up. I use a blender to crush them, but that's optional. You can crush them in a baggie or the empty bread bag too.
Today I had some hamburger rolls in the freezer, and I needed to use them up. Cut up the bread in chunks that are generally the same size
Place them on a cookie sheet. Spread them out as much as possible.
Set oven to 350F. Place the cookie sheet on the middle rack and cook until the chunks are bread are browned. (appox 20 minutes) Keep and eye on them, and be careful that they don't burn!
Put bread chunks into the blender a few at a time, and pulse until all have been crushed. If you don't have a blender or a food processor, you can simply put the bread chunks into a large baggie or bread bag and roll over the bread in the bad with a rolling pin or other rounded object that gets the job done.
Place them in a gallon sized baggie and keep them in the freezer. When you need bread crumbs for a recipe, just take out what you need.
You can use some of your home made bread crumbs to make shake and bake pork chops!