You can effectively draw things to you whether or not you know the specific form, amount, or appearance of the items you want. You do need to know their essence, however. The essence of something is the function you want this item to perform, the purposes you will use it for, or what you think it will give you. Many things other than what you picture might give you the essence of what you want, so be open to letting what you want come in whatever way, size, shape, or form is most appropriate. Think of something you want to draw into your life. What is the essence that you want from this?