Uncertainty is a prime driver for procrastination. If you aren’t sure how to further decompose the task at hand, you can create a surrogate by using time blocks. Commit that you will work for some prespecified time without taking a break
By choosing a time limit for how long you will work on the task in the present sitting, you will bring the task into finite bounds and reduce the psychological blocks associated with interminable activities.
By sticking to the task for the chosen time, you will generate many of the same positive feelings and momentum that you would find in actually completing the task, which will further assist you in doing that later.