Crease Patterns are the roadmap to an origami model; in simpler words, it is a combination of folds which relates to a particular base or design that the folder is familiar with. It is said that one who has ample knowledge about this art can fold the structure just by looking at the crease pattern of that particular design. But crease pattern is not always as easy to comprehend unless you are a pro in interpreting lines and symbols on a paper. So to ease this dilemma to some extent, take a look at this informational video by Tadashi Mori, where he talks about how to solve or decode a crease pattern in order to create a meaningful structure out of it.
You can also generate your decoding patterns to solve the crease; it's only a matter of practice and perseverance.