You could do it like this:
ULONG tags[] = {P96SA_Width, 800, P96SA_HEIGHT, 600, P96SA_Depth, 24, P96SA_Title, "doodie", TAG_END};
screen = p96OpenScreenTagList(tags);
But I'd rather use CGX than P96, because it runs on all graphics boards not only on P96 ones. CGX programs run on P96, not vice versa.
And additionally I would by all means avoid using graphics card-only funktions. If you'd use OpenScreenTags instead of p96OpenScreenTags, the program could run on non-graphics card systems also.
Bye,
Thomas