I setup SD3 with multiple channels for the drums I wanted after loading a Steven Slater kit. No problem with the interface and the mixer, the drums are all there and I assigned them to the tracks I wanted. But when I open the sequencer all I get is keyboard numbers and no sound. There should be drum names in the rows but there aren't any. It's worked before but now I can't get it to.
Any ideas ?

oops, wrong button

=)) u found it fast, some my errors costed to me much more

so you opened Session drummer 3's GUI. then clicked on the step sequencer button ?
as seen here https://www.youtube.com/watch?v=py_xQgNQnjA
but still see keyboard numbers ?
 
sounds like you might be in the Piano roll view instead. which is possible.
just close that view and reopen in step sequencer.
I myself prefer the Piano roll view as you can see here by this video I made a while back
Drum editing in the Piano roll view:

 
but the sequencer is a great drum editing tool.

I don't have the piano roll open, it's the sequencer, it even says so on the bottom of the screen. I've used it before and I'm using the Master Class tutorial from Cakewalk. But for some reason it just won't open correctly. Also, there is no signal when I click on any of the buttons. Although, when I go back to the drumkit page I can hear all of the drums on the screen and in the mixer as well

this is what I'm getting, as you can see there are no drum names in the rows and no sound, even though I have a program in SD3