Hi everyone: I didn't get a chance to play last night. I fell asleep right after dinner and that was it for the night!
Anyway, Alice I use the summoning dolls all the time to fight for me. I'm not as far along as you are, so I don't know if you absolutely have to use them, but it's not hard.
Go into your inventory and click on a doll, and it will appear next to yours and DK's pictures on the upper right. It will have stat screens and everything else that you have, so if they're fighting for you make sure to keep an eye on that. They can use potions, just the same as you. Don't forget that you have to include them in your party to get them to move along with you by clicking on F4 so everyone in the party moves together.
If they get killed, there is a little bit of a wait before you can use them again, although you can click on them in your inventory and they'll show up on the screen. You'll just see light swirling around them until they're ready.
One thing I've found that is handy is if I don't want them, or if they get stuck in a wall, I can click on them in the inventory (while they are part of my party) and that will take them out of the party. Reclicking will bring them back in. This can come in really handy.
I also use them to lug around stuff for me when me and Dk have too much to carry.
Make sure if they're going to fight for you to give them weapons and armour. Check them occasionally to make sure to do repairs when needed.
I hope this helps! They're really useful. It's fun to watch because sometimes I want my party to go one way, and half of them split up and run around to another door, just as if they have minds of their own!