Putting together a overflow question


New member
I am doing the Dursostand DIY overflow, my question is do i need to put any sort of cement/seal to hold the connectors together? Like for the top part where i cap the top of it i figure to put on the tape to make it water tight, but do i need to seal each pvc pipe together or can just put them on and let it go since it' sin water anyway?

Here's pic to help describe what im making from them:

Need to cement or what's it called between each pvc pipe? Like where #10 is i replaced that with a screw on top that i will drill a hole into..