If you don’t know where to start, do the stuff that’s quickest to do.
The hard stuff is important and it needs to be done.
But, if you were completely sure about it needing to be done right away, then you’d already know where to start.
The fact that you don’t know means that you need a boost in momentum.
The stuff that takes a short amount of time might not be the most important stuff, but it will give you a sense of accomplishment.
This motivation is important when you’re in a position of doubt.