Do I need to run two Media Baskets?

inTank strongly advises the use of two Media Baskets - one on the left intake chamber and one on the right intake chamber.  This will insure that detritus is caught under both intakes - keeping the rear chambers cleaner and reducing the risk of problems that arise like nitrates, particles floating in the water or a crash.

Ultimately the decision is up to the user - the Media Baskets do not need each other to function.  You can add a second at any time.

Is there a left and right Media Basket?

No.  The Media Basket has a universal chamber design.  It will fit on the right - or left intake chamber and function the same.

What is this black part and how do I install?

This is a custom water director.  It will block off a gap in the Fluval chamber design and allow more water to enter the top of the Media Basket.  Please install as shown on this picture.