I set up my "Active/Training" alert schedule for what I want my troops to do in normal times. I also have an alert called "Live Training", which has it's schedule set so all of my melee squads defend my "melee training" burrow every month, which is the room that I pit goblins into for, well, live training. So when I want to do live training, I set my melee squads to the Live Training alert, and they all proceed to the training room.
One wall of the training room is fortifications, behind which is a hallway. There is a burrow called "Archery Training" that covers that hallway. The archer squads are all scheduled to defend that burrow in the Live Training schedule. So when I put them on the Live Training alert, they go into that hallway behind the fortifications and are ready to shoot whatever gets dropped in the training room. It's better than stationing them there with the squad orders, because half of them would end up in the training room instead of in the hallway if I station them. Defending a burrow makes all of them go into the burrow. When the training is over I switch all squads back to the Active/training alert and they go back to whatever they would normally be doing that month.
You can also use this during attacks. Assuming you have an alert set up for getting your civilians into a burrow, you can also set up a schedule that sends each squad to where you want them during an attack. You have to put each squad on that alert (just setting the civilian alert doesn't effect your squads), but it's easy to remember to do, and then your archers go to their shooting spots, and your melee troops go to wherever you want them.
It's actually quite useful, once you learn to use it.