exhaust installation

Hey guys. I have started to install a new complete exhaust system to my 90. I have fitted the down pipe and then the mid pipe. between the 2 I have put an olive connection. But when it comes to fitting the mid silencer and back box, am I supposed to put the olive rings between these connections or not, only the connection between the mid silencer/mid pipe and mid silencer/back box, dont seem to go together.

I have just come across these, do i need them if so where do they go?
Land Rover Parts Shop

Any help will be much appreciated

Thanks