Job To Be Done is the first concept you should explore in the Marketing Canvas. It is under the Customer category. It helps you to understand if you really know the people that are buying/using or might buy/use your products and services.
If you want to design the marketing strategy for your business, you should first start to analyse where you will play. What does it mean? It means that your product/service will be associated by consumers/buyers with other alternatives they have on the market (maybe no alternative exists which means that you creating a new category also referred as a blue ocean).