Engine protects your files from scans. Ex; Downloading clockwork's hack and then protecting it will make it even harder for VAC to detect that you're using the hack. But by many reports, and if you're a obvious hacker, you'll get smashed by OVERWATCH. But to answer your question fast, It'll help you from not getting detected by VAC and make it much harder to be found. Or not even to be found ever?!
EDIT- How to use? - I can't make a video of it and explaining it would be to difficult for me. Try watching a youtube video on it?