On a browser, they are at the top and show all three tabs, with the barracks troops first. As far as actually using the troops, I find the cerberus very useful; I use it almost exclusively against mages.
One thing that's good to note if you autofight. Try to use the fewest different kinds of troops possible. I've noticed that if I have to use four or five different kinds of troops, I lose those more often than if I can use one or two different kinds. For example, if I have, say, 3 mages and 2 heavy melee as my enemies, then it's better to use 5 archers to fight them than to use 3 cerberus and 2 mages. It just seems to me like the AI in autofighting is able to win more if it has less different kinds of troops to move around the board. And of course, order is important, but the order gets messed up in spire fights where you have 2 or 3 waves and can't rearrange your troops.
I hope all that makes sense; I haven't had my coffee yet this morning.