I, too, procrastinate when I am not sure how to do something. Actually, so much so, that my favorite saying is:
If it wasn't for the last minute, nothing would get done.
The 'last minute' has served me well over the years and it is amazing to find out that once you start, it wasn't as hard as you thought. In fact, I usually find that I am kicking myself for not starting sooner, as I sit there trying to finish the project bleary-eyed 3 a.m. in the morning. Then I remind myself the the tennis shoe saying by Nike:
Just do it!
Take that first step... it isn't as hard as it looks.