soupy - you can tangle horizontally or vertically, and with either hand high or low.
Coleman was just describing one type of tangle, which he considers the easiest (and i agree). If you find it easier to tangle horizontally, which lots of people do, then go for it.
Your hands should stay in the same alignment and move across your body like they're connected by invisible scaffolding. Don't rotate them at all.
make sure the poi don't do any beats
inbetween your arms while moving them. The heads should move from the left of both arms to the right of both arms at the same time. Not past the left arm first, and then past the right arm.
Don't get demoralised. It's really tricky to start off with. Especially if you don't have anyone to watch doing it.
Also the poi that you use can make things much easier, or much more difficult. Like FiregeeKs noticed, ordinary chain is pretty tricky to tangle with. i highly recommend learning with fairly heavy balls (like juggling balls) inside long non-stretchy socks.
my final words of advice: go slow, and examine the tangles that don't untangle to find out why they didn't