During reassembly:

If any front-facing camera copper tape is still on the logic board, use tweezers to remove it.

Use your finger to press the front-facing camera into its recess.

Remove the larger, clear liner from the front-facing camera copper tape to expose the adhesive.

Carefully place the copper tape onto the camera so the skinny end points toward the bottom of the phone.

Use the flat end of a spudger to firmly press the adhesive into place, securing it to the camera and logic board.

Remove both remaining liners from the copper tape.