According to the directions, the glue takes 24 hours to dry.
If someone says that something is true according to a particular person, book, or other source of information, they are indicating where they got their information. Philip stayed at the hotel, according to Mr Hemming He and his father, according to local gossip, haven't been in touch for years
If something happens according to plan, it happens in exactly the way that it was intended to happen. If all goes according to plan, the first concert will be Tuesday evening
If something varies according to a changing factor, it varies in a way that is determined by this factor. Prices vary according to the quantity ordered
If something is done according to a particular set of principles, these principles are used as a basis for the way it is done. They both played the game according to the rules