With Gotcha Day, you can include pictures, stills from a video if you have one, and a play-by-play of the event. Also included in Gotcha Day can be Adoption Day information if you like.
The most important thing to include here, of course, is the way you became a family. This may or may not be the place to describe your child's sadness and fear at your presence. Perhaps you want to talk about that first, long night. Perhaps not?
Because Mae's book is geared for a young child, I describe the day briefly yet with great care. She knows she was confused and scared; she knows she was "the screamer" of the group. But she also knows I gazed at her all night long in amazement and love. In this way, she knows that, yes, she was scared, but it was ok.
If you get together with your adoption group at all, this is also a fun place to include the names of your child's "orphanage sisters" with some fun tidbits about them. We always point out Sophia, with her beautiful long hair, who was Mae's crib mate. And we always tell stories about Zoe, since the two girls clearly recognized each other and were probably "good buddies" in the orphanage.
You can also let the pictures do the talking and only comment briefly, i.e., Gotcha Day at last! In this way, you are opening the door to talk about this page each time your child opens to it. Either way will work. And both ways will give your child a special glimpse into her first day as a member of her family.