Zip mode in Myst IV

Can someone remind me how to add sites to the zip button? I'm getting tired
of taking the water taxi every time I want to return to the Observatory, but
I can't seem to add a scene to the catalogue. I don't recall having a
problem before.

Also, the locked door in the botany building - am I supposed to be able to
get thru it? I suspect I have to come at it from the other side, where ever
that is...

~RL

Locations are automatically added to the zip toolbar when you visit
them. Click the arrows to the left and the right of the toolbar to
cylce through the locations.

You'll find out where that door leads later in the game.

Cheers,
- Deg -