Visualisation and planning
Derek Cohen (in Perth, Australia)
As a psych who has worked a great deal with ADHD and other neurodevelopmental disorders for over 3 decades, it is so evident how the planning and organisation skills of individuals are impacted when they have difficulty seeing the Big Picture.
One of my standard ("dad") jokes-come-explanations to parents is to ask them, "Where would you start given a 1000-piece jigsaw puzzle to complete?". 9.9/10 say, "Oh, I would begin with the corners ... or the outline". Then they look very confused when I say that this is possibly the 2nd or 3rd thing to do (and, no, it is not taking the pieces out of the box!) 
The first thing to do is to look at and examine the picture on the box. That is the big picture. Only then are you in a position to place pieces seemingly randomly on the table top ... because by now you understand how all the pieces are connected.
The same is apparent when following the construction of furniture. You see the outer shape, and then you need to create an exploded shape, before recognising the order in which these need to be done. Some can do this mentally, and some just cannot at all.
There is a simple solution for those feeling overwhelmed. If you cannot visualise it, find photos and videos on the project, especially the latter if possible. Find similar versions. Look at the joinery/construction.
Some designs need to be constructed in reverse, such as the dados need to be made before the case is assembled. And if you want the drawer blades to be aligned, you need to find a way to make them so ... so when and how will this done? An example of this were my recent posts about preparing the way for placed freshly-glued up drawers in the drawer case ("Dovetailing for Blood!").
We need to zoom in and zoom out (as I call it): zoom out to the big picture, then zoom in to the detail, then zoom out again for context ... and zoom ....
If you find this overwhelming, or difficult to remember, use photos or drawings. This is why a pictorial essay is so powerful. My photo essays are a record for me, but equally as much a method of communication with others.
Regards from Perth
Derek