"He shows her a dress and she gets it."
Translation:Han viser hende en kjole og hun får den.
Maybe I know now. She gets the dress, "it" refers to the dress, a dress is "en kjole", so it is not neutral, I assume that is why it is "den" and not "det". I think if the sentence was "he shows her a mirror and she gets it", it would be "han viser hende et spejl og hun får det"
- "Forstår du det?" if you mean understand.
- "Får du det(/den)?" if you mean receive (unlikely, because the English you have provided is contextually wrong for this). (Further, I suspect får can’t be used to mean something like understand in the way that get can in English.)
bab.la also (for catch-on) suggests:
... but be aware that none of the examples given there seem quite to cover the meaning of catching-on.
Disclaimer: I am a beginner in Danish. So we can both only hope I have not provided inaccurate translations and usage comments.