The goblin alone doesn't have to do anything complicated. Your final goal is to create a stepping stone here:
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×
Then you can get the goblin to stay on the pressure plate. Until then, the only thing it does is get in your way while you lead the constructs around. To minimize this, try to use the corners of the room to trap it and then work on moving constructs on the opposite side. Fortunately, you only need one goblin alive, so get rid of the other as soon as possible.
Your main method of progressing is
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×to create stepping stones so you can move construct parts onto them, then lead the constructs towards the next place you need a stepping stone.