1. Get The Software
Okay, first you need the right software on your computer to do it. It can be difficult finding software online that is actually trustworthy, but I asked +Maria Sinayskaya, owner of goorigami.com, for recommendations. She told me about inkscape, a program that is completely free and is basically perfect for Origami Diagramming. It isn't specifically designed for Origami Diagramming, but for any sort of diagramming, but it works very well. Check out their website by clicking their name. To get the install package and install immediately, (works for PC and Mac) then click here for the Windows version, and here for Macintosh version (see more info on downloading inkscape at inkscape.org/download/?lang=en) . You can also do other software, like doodle, but this is the software I use.
When you first open it, inkscape should look like this:
2. Know How To Work The Software
It can be confusing or even hard the first time you use diagramming software. But once you get to know the tools, it isn't so hard anymore. Make sure you set aside at least an hour to get to know the tools, and feel free to experiment. You don't have to save anything that you think looks lame. Take time to learn how every tool works, and all of the basic commands that you will need to know. Here is part one a video explaining how to use inkscape to do Origami Diagrams:
3. Just Do It!
Once you know how to work the software, the rest is easy! Just simply make a diagram! That's basically all it takes! If you need any additional help using inkscape, feel free to comment on this page and I will help you as best as I can.
There you go! Now you can diagram your Origami projects! Hope you got all of the information you needed! Thanks! Have a terrific time diagramming!