I was searching the forum about this topic and the solution was eather buying 80 euro adapters or watching a video that is no longer available for diy. Looking more in depth I've found this on a SK forum, I hope there is no issue sharing it here.
When you are searching for the tail lights 5E5 = sedan, 5E9 = combi, and be sure that the bulb carrier and harness is included!
Link to buy the adapters:
(Sedan) https://www.cars-equipment.com/en/shop/tail-lights-3/led-tail-light-adapters-from-octavia/
(Combi) https://www.cars-equipment.com/en/shop/tail-lights-3/led-tail-light-adapters-from-octavia-2/
All the parts can be found on aliexpress, the connector should come with the wires and pins so there is no need to buy them individually, check the listing
Option 1 - Make an adapter:
2x 3C0972733 (Combi)
12x N10336105 (Combi)
2x 1S0972706 (FL)
6 wires 0.8 - 1.0 mm2
2x 191972716 (Sedan)
12x N10318905 (Sedan)
12x N10335807 (FL)
6 wires 0.8 - 1.0 mm2
All the parts can be found on aliexpress, the connector should come with the wires and pins so there is no need to buy them individually, check the listing
Option 2 - Cut the old connector, follow the wiring scheme to add the new connector so it will look like it came from the factory:
2x 1S0972706 (FL)
12x N10335807 (FL)
New coding required:
To enable both rear foglights: