Simple process but needs a blender, food dehydrator and grain or coffee mill. Storage should properly be in a vacuum sealed jar, which means you need a vacuum sealer too. You may (my opinion) be able to use oxygen absorbers in the jar if you lack the vacuum sealer. Either way, the jar must be sealed air-tight.
Note that the eggs are first scrambled without anything added, just plain eggs. Read the lead-up about what failed for the author.
http://www.askaprepper.com/how-to-make-powdered-eggs/