From manual:
PANEL* splash = pan_create("bmap = splash.pcx;",1);
set(splash,SHOW);

Also:
A6 Templates had good startup menu code in it-- fading screen in. There is a template_6 folder in A7. You might want to look in there for menu related code.

Coding the splash/menu/audio/video settings is tedious at first, but it's not so bad once you get into it.