Bonjour Jose,
Here is a lesson Laura has written that speaks to this subject:
https://www.lawlessfrench.com/subjunctivisor/des-que/
Also, here is another lesson on the same subject from a different source:
https://www.francaisfacile.com/exercices/exercice-francais-2/exercice-francais-73036.php
At times when I become stuck on a topic, I will use a different site reference that can provide a different perspective on the topic. I find that usually provides an explanation that compliments
this site.
J'espère que ma réponse vous aiderait.
Bonne chance et bonne continuation dans vos études en français, la langue de Molière et qui a été utilisé par le monde français depuis l’époque d’Hugues Capet

Ron (also a non-native speaker)

Thanks!