To process one has to say not much. The cut edges are clean and kept the heatsink by 3M tape, which probably is not a thermally conductive adhesive, but still provides good thermal contact. At least the aluminum fins are warm.
The second small heatsink (for the voltage regulator) need in my opinion not place unless one uses a 5V power supply, because it (at least for my Raspis) shows little heat and therefore nothing needs to be additionally paid.
