Is there a switch in the admin that toggles or a choice can be assigned what shows up on the main (or landing) page for the gallery?
Currently it just shows the header and menu, and that's it. I would prefer to have the latest upload appear, or at least a choice of different categories, etc.
reading the docs should be the first thing you do if you have any questions. Then you search the board (and I mean searching: re-phrase your search terms if you don't get the expected results in the first place) and the FAQ and read the stickies. Only if you don't come up with an answer, then you should post.
Your question has been asked very often already, and it is in the docs: http://coppermine.sourceforge.net/manual.php#changing
Joachim