Opposite to the Telegraph headline Having a messy desk makes you 'more creative', a messy desk does probably not make you more creative, but creative people produce more mess. Or, in other words, making a mess is definitely a part of the creative process.
What do I mean by that: If you want to be creative you will first have to play around with the tools you have at hand. And during this process it is important to just try something without thinking too much about the ultimate goal. Part of the process is just to do something, see what happens and then start over, until eventually, you arrive at something you like.
The part of making a mess might involve writing down fragments of sentences onto a sheet of paper or typing it into a text editor. It might also involve drawing all sorts of funny ideas onto many sheets of paper, or even drawing the same thing over and over again while refining it in the process. Or, when writing software, it involves creating many different versions of the same software while refining the structure of the code.
Of course, at some point you might end up having to prepare a final version that you want to deploy. This is then the least pleasant part, it's the part when you need to file through all the ideas that you've produced and pick the gems out of the dusty ruins. At this point you need to be able to remember what you did and where you roughly did that.
I think Christoph Niemann summarized this process quite nicely in Abstract: The Art of Design: You want to „be a much more ruthless editor and at the same time be a much more careless artist.“ He also summarized this process nicely in this article for the New Yorker.
Thus, you want to iterate between being a careless and almost child-like artist and on the other hand being a ruthless editor that drives the iterative process into the right direction.