Applications in OS X are by default assigned to the current desktop, so if you open a program and then switch to a different desktop, the program's windows will stay on the current desktop. However, there are a couple of ways to change this, so specific programs open on a different desktop, or so they remain present on all desktops.
The first option is to assign a program to all desktops, which is the most straightforward option. To do this, simply add the program to the OS X Dock, then right-click it. In the contextual menu that appears, choose &… Read more