A-frame box practice

Re-read the first steps of the Clean Run article and realized I've been missing the step of throwing the treat into the box before throwing a treat outside of the box. So we gave that a try at the field today (box on ground, now with additional sponge at corners for slightly better visibility in grass). She was having fun, but when I back up from the box she tends to come to me, then upon getting no reinforcement she turns around and goes into the box but it's from the side rather than the "top". Hmmm. Might just be worthwhile to buy the DVD they're putting together on this training method.