need advice on "living in the end" from experienced and successful manifesters.

does this mean just firmly believing my desire is already fulfilled in the 4d and 3d is playing catchup(like an amazon delivery that hasnt arrived yet) or do i literally need to delude my brain into thinking what i want is already here and the present 3d is lying to me?

i can easily do the former, but find it very difficult to do the latter but i want to know if it is necessary from an experienced manifester.