WHat is the code to open a program in cmd?

Im trying to make a thing that when you click it, it opens certain programs which in the case is going to be all my internet browsers. But how do i do this?

Is the code something like

start C:\Program Files\Mozilla Firefox\firefox.exe

ANd then save it as .bat?

Almost.
You should put the path in double quotes and remove start:

"C:\Program Files\Mozilla Firefox\firefox.exe"

That's all there is to it.