When it comes to manifesting, one rarely excludes any details of their desire. Most manifesters have a vision in their head of something they truly desire to see in reality, and they want to ensure that it comes out exactly as imagined. While this no exceptions mentality helps maintain positive beliefs, you may be surprised to know that many of the details you don't include will often be of great benefit towards creating your reality.
Alchemist, the world around you contains many unknown variables. As creators, it would be insane to try and control every aspect of our universe at once. So instead, allow the world to shape itself according to your desires. Doing this would require you to practice nondoing, to flow with the current of life instead of swimming against it.
Just think of how many forces are at work just by the simple act of walking. There's gravity pulling you down, kinetic energy pushing you forward, muscle fatigue, body symmetry, the list goes on. But to walk, you need only one thing, a direction. When children first learn to walk, they don't study the fundamental dynamics of movement. Typically, children will want to reach one of their parents on the other end of the room, usually encouraged by tons of cheering.
Similarly, with manifesting, intent is all anyone needs to bring reality into being. Just by wanting to inhabit a general state of being, like happiness, your vibration will naturally gravitate towards a happy reality naturally and effortlessly.
Effortless achievement is nature's way, and it is also the key for humans to create the realities they want while still being ignorant of all the forces at play.