dahinter
behind it
Indicates a position that is at the back of something or behind something.
Das Haus ist groß, und der Garten dahinter ist wunderschön.
The house is big, and the garden behind it is beautiful.

behind it
Loading your saved state.
behind it
Indicates a position that is at the back of something or behind something.
Das Haus ist groß, und der Garten dahinter ist wunderschön.
The house is big, and the garden behind it is beautiful.

'Dahinter' (behind it) is a pronominal adverb made up of 'da' and the preposition 'hinter' (behind). It literally means 'behind the/that' or 'behind it' and refers to something that was mentioned earlier.
Siehst du die große Tür? Dahinter ist der Konferenzraum.
Do you see the big door? Behind it is the conference room.
'Dahinter' (behind it) replaces the combination 'hinter + noun' in order to avoid repetition. You use it when the place or thing is already known.
Vor dem Museum ist ein Parkplatz. Dahinter beginnt ein kleiner Wald.
In front of the museum is a parking lot. Behind it begins a small forest.
In its figurative meaning, 'dahinter' (behind it) is often used in questions or fixed expressions to investigate the real reason. Very common are 'Was steckt dahinter?' (What's behind it?) or 'die Absicht dahinter' (the intention behind it).
Sein Angebot klingt zu gut. Ich frage mich, was dahinter steckt.
His offer sounds too good. I wonder what is behind it.
The expression 'dahinter sein' means that someone is trying very hard to make sure something gets done. It is often followed by a construction with 'dass' (that) or 'zu' + infinitive.
Der Chef ist dahinter, dass das Projekt pünktlich fertig wird.
The boss is on it, making sure that the project is finished on time.
behind
'hinter' and 'dahinter' can both describe a position at the back of something or after something else. 'hinter' is a preposition and needs a noun or pronoun: 'hinter dem Schrank' (behind the cupboard), 'hinter mich' (behind me). 'dahinter' is an adverb and replaces this whole place expression when it is already clear what you are talking about. For example, you first say 'der Schrank' (the cupboard) and then 'dahinter' (behind it). Learners confuse them because the spatial meaning seems the same. In practice: 'hinter' needs a complement, while 'dahinter' refers to something already mentioned.

Neben der Schule steht eine kleine Sporthalle; dahinter beginnt der Park.
Next to the school there is a small sports hall; behind it, the park begins.
Die Gruppe wartet hinter dem Eingang auf den Kursleiter.
The group is waiting behind the entrance for the course instructor.