MFC multiple dialogues

Hello!
Sorry for this newbie Q about MFC, but i'm just starting out and Microsoft seem to like making things confusing...

I am just making a simple app with multiple dialogue windows (kinda like what most simple VB progs look like).
I'm using MFC for this, so and am making a class for each dialogue (I understood that much)

However, i can't seem to open one dialogue from another. How is this done?
i.e. when i click a button in Dialogue1, i would like dialogue2 to open and be the active dialogue....

thanks

In the button handler declare an instance of the second class and call DoModal (or Show) on it.