Here "heart" stands for the entire person. The abstract noun "desire" can be stated as a verb. Alternate translation: "what you desire" or "what you want" (See: [[rc://en/ta/man/jit/figs-synecdoche]] and [[rc://en/ta/man/jit/figs-abstractnouns]])
The abstract noun "plans" can be stated as a verb. Alternate translation: "may he help you to accomplish everything that you plan to do" (See: [[rc://en/ta/man/jit/figs-abstractnouns]])