Simply attach the bezel onto your Macbook and use the rubber seal that surrounds the screen to align the bezel.

Depending on where you purchased your replacement bezel from, you may not have double-sided tape pre-applied. If not, put a strip of double-sided tape on the top edge of the bezel.

The double-sided tape that Apple uses on the bezel is 4mm. I'm not 100% sure but this could make sure the tape doesn't stick to the delicate ribbon cables.