Okay that Primer is not obvious to people's eyes, and I found that by mistake when I was button-bashing while walking on that path. What I did was start off walking from the Al Bhed Agency place with the chocobo pen and keep walking to the trails. Once you're on the road, keep hitting your main button (circle for jap etc, cross for us etc) along side of the grassy area on the road. Just keep searching around the big bend there and you should find it with surprise.
