Guild Wars 2

I may be an idiot but I don’t understand how you get the pumpkins to spawn skeletons. It says you should bring them to your teams little houses(don’t remember the name). But when I bring the pumpkin there I see no option to spawn the skeletons. What am I doing wrong?

throw pumpkins inside the things you have to protect and they come out of the ground

thank you. victory will be mine.