Bevor ich die Tassen in die Spülmaschine einräume, spüle ich sie kurz im Spülbecken ab.

Because bevor introduces a subordinate clause. In German subordinate clauses, the conjugated verb normally goes to the end.

So:

• Bevor ich die Tassen in die Spülmaschine einräume
• not Bevor ich einräume die Tassen ...

This is one of the most important word-order patterns in German.

German main clauses follow the verb-second rule. The conjugated verb must come in the second position.

Here, the whole bevor clause comes first and counts as position 1. So the main clause must begin with the verb:

• Bevor ..., spüle ich ...

If the main clause came first, then you would say:

• Ich spüle sie kurz im Spülbecken ab, bevor ich die Tassen in die Spülmaschine einräume.

Because abspülen is a separable verb.

In a main clause, the conjugated part goes in the normal verb position, and the prefix moves to the end:

• Ich spüle die Tassen ab.

In subordinate clauses or infinitives, the parts stay together:

• ..., weil ich die Tassen abspüle
• die Tassen abzuspülen

So in your sentence, spüle ... ab is completely normal.

Because einräumen is also a separable verb, but here it is inside a subordinate clause.

Compare:

• Main clause: Ich räume die Tassen in die Spülmaschine ein.
• Subordinate clause: ..., bevor ich die Tassen in die Spülmaschine einräume.

So separable verbs:

• split in main clauses
• stay together in subordinate clauses

This is about case after the preposition in.

German in can take either:

• accusative for movement toward a destination
• dative for location

Here:

• in die Spülmaschine = movement into the dishwasher, so accusative
• im Spülbecken = location in the sink, so dative

That is a very common German pattern.

Im is a contraction of in dem.

So:

• im Spülbecken = in dem Spülbecken

German often contracts common preposition + article combinations:

• im = in dem
• am = an dem
• zum = zu dem
• zur = zu der

Because once the noun has been introduced, German usually uses a pronoun to avoid repetition, just like English does.

So instead of repeating die Tassen, the sentence says sie.

Here sie means them and refers to die Tassen.

Die Tassen is the accusative plural here, because it is the direct object of einräume.

For many feminine plural nouns, the nominative plural and accusative plural look the same, so you just see:

• die Tassen

That can be confusing for learners, but it is correct here.

Kurz is an adverb here, meaning something like briefly or for a moment.

It modifies the action abspülen. Its position is natural in the middle of the clause:

• spüle ich sie kurz im Spülbecken ab

German adverb placement is somewhat flexible, but this version sounds very normal.

Yes. In German, subordinate clauses introduced by words like bevor, weil, dass, and wenn are separated by commas.

So the comma after einräume is required.

Not here.

Use bevor before a clause with a verb:

• Bevor ich die Tassen einräume, ...

Use vor before a noun phrase:

• vor dem Einräumen
• vor dem Essen

So bevor = before + clause, while vor = before + noun.

Yes. German often uses the present tense to describe a sequence of actions, especially for habits, routines, or near-future actions.

So this sentence can sound like:

• a general habit
• a usual routine
• something happening now or soon

German does not need a special future tense here.

Because they are related to the verb spülen.

German often forms compound nouns this way:

• Spülmaschine = dishwasher
• Spülbecken = sink / wash basin

Learning to recognize these compounds helps a lot with vocabulary, because German builds many nouns from smaller familiar parts.