I really like the looks of that Motion Pro alignment tool. In this case a picture is indeed worth thousand words.
A Profi CAT dot or line laser chain alignment tool is also an option (significant $$$ though)
youtube [url=https://www.youtube.com/watch?v=Zwp-uDlp14I]link
I bought the Motion Pro chain alignment tool and found it tricky enough to use without removing the chain guard. I've now tried the new version of the Profi Cat line laser (magnetic version), and find it easier to use as it attaches magnetically to the sprocket and shines the laser along the top edge of lower part of the chain. I'll stick with the laser in future. Price was €75 incl VAT and postage from Germany.