Cook on HIGH for 4 hours without opening the lid during the cooking time.
When the cooking time is up, add the contents from the slow cooker into a blender. Pulse until a jam forms. DO NOT OVER BLEND OR YOU WILL MAKE CRANBERRY BUTTER. You can use an immersion blender if you choose.
The jam will thicken a lot while it cools, don't fret. Cranberries have pectin in them.