The Combat Engineer rules first came out in Shockwave if you have that. They are also in Ogre Miniatures, which you have access to in PDF form if you pledged the Kickstarter. You can adapt the minis rules back to the hex system by simply translating 2" to 1 hex. There are other differences, but they don't matter for Combat Engineers.
So I'll keep singing the same refrain: go to e23.sjgames.com and download The Ogre Book, Ogre Miniatures, and The Ogre Scenario Book. Your time with those works will be well spent!