With Real Madrid's current position in 20th place, then most likely the play-offs scheme or result simulator will be like this that will be faced by Real Madrid. However, all that will change if Real Madrid's position also changes. This will depend on the results of the next 2 matches where Real Madrid will face RB Salzburg and Brest.
Source: UCL Result simulator
Salzburg and Brest are two average team of which if comparing to Madrid I'm their former formthey would see this as a very easy game for them to win without necessarily having to really struggle because this two team will be considered weak with respect to their own form and strength, then even experience wise, they have even better experience than this two teams put together so Madrid by almost every standard is at advantage ahead. I believe and hope Madrid is definitely going to scale through this point of the league and try to do better at the next stage.Source: UCL Result simulator