Here's a You-tube video, with some explanation and pictures (same pictures you see on Integra screen or in the owners manual)

https://www.youtube.com/watch?v=EEEiYLl1TPU

I mainly use Adaptive curve, because I'm on the free WAAS signal.

{Note: the one time, I tried "identical curve"(first pass), everything(Integra and GPS 1600) was brand new to me, and I was spreading Fall dry fertilizer, by counting old corn rows. I was in a rectangular field, with straight rows, but field does have some "roll" to it. Running North to South. It seemed to me that the identical curve guidance line keep getting further and further away from where my actual number of corn rows "told me" to turn in at. (I assume maybe some of this is WAAS drift) This field is probably the easiest to plant, that we have; so my thinking is that the planter should have been pretty darn close to the correct width, from North to South rows and following planter's marker}

Since then, I've only used Adaptive curve (last pass) and using the Free WAAS signal, seems to work for me. [note: I don't save guidance lines = not worth it on WAAS signal]