SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

My husband and I are trying to run sprinklers in the backyard. Our frontyard is hooked up to rainbird esp controller. We bought the expansion module for 3 more zones. My question is how do we wire it? I am not sure where the common wire goes, since the first zone is using that space and the extension only has 3 screws to use. Do we have to splice the common at the first box and run it to the second? I haven't had much luck trying to find a solution on rainbird's website for wiring an expansion module. We did get 4 multistrand wire.