Bevor wir gehen, räume ich die Bohrmaschine weg und will das Zimmer noch einmal lüften.

Because bevor is a subordinating conjunction. In German, a subordinate clause sends the finite verb to the end.

• Main clause: Wir gehen.
• Subordinate clause: bevor wir gehen

So Bevor wir gehen follows the normal subordinate-clause pattern.

Because the whole clause Bevor wir gehen comes first and takes up position 1 in the sentence. In a German main clause, the finite verb must be in position 2.

So the structure is:

• Position 1: Bevor wir gehen
• Position 2: räume
• then the subject: ich

That is why you get:

Bevor wir gehen, räume ich ...

and not Bevor wir gehen, ich räume ...

wegräumen means to put away, to tidy away, or to clear away.

So die Bohrmaschine wegräumen means to put the drill away after using it.

It is a very common verb in everyday German for putting objects back where they belong.

Because wegräumen is a separable verb.

In a normal main clause, separable verbs split apart:

• Ich räume die Bohrmaschine weg.

The conjugated part goes in the usual verb position, and the prefix goes to the end.

But when the verb is an infinitive or in a subordinate clause, it stays together:

• Ich will die Bohrmaschine wegräumen.
• ..., weil ich die Bohrmaschine wegräume.

So in your sentence, räume ... weg is exactly what we expect in a main clause.

Because German often leaves out a repeated subject when two verbs share the same subject and are linked by und.

So:

• räume ich die Bohrmaschine weg und will das Zimmer noch einmal lüften

means the same as:

• räume ich die Bohrmaschine weg und ich will das Zimmer noch einmal lüften

The second ich is understood. Omitting it sounds natural and avoids repetition.

will is the present tense of wollen, which means want to or intend to.

Here it expresses a straightforward intention:

• I want to air the room one more time.

möchte is softer and often more polite, especially in requests:

• Ich möchte einen Kaffee. = I would like a coffee.

In a simple statement about your own plan, will is perfectly normal.

noch einmal means once more, again, or one more time.

In this sentence it suggests:

• the room has been aired before, and
• the speaker wants to do it one last time before leaving.

In everyday speech, people often say noch mal, which means the same thing.

The verb lüften means to air out or to ventilate.

German commonly uses it as a transitive verb with a direct object:

• ein Zimmer lüften
• die Wohnung lüften

So das Zimmer lüften literally means to air the room out.

English often uses a longer expression such as air out the room or open the window to let fresh air in, but German can express that idea with the single verb lüften.

German uses articles more often than English does. When talking about a specific room, das Zimmer is the natural choice.

Here it means a particular room that both speaker and listener can identify.

So:

• das Zimmer lüften = air out the room

Using just Zimmer here would sound incomplete or unnatural.

die Bohrmaschine is in the accusative case because it is the direct object of wegräumen.

The speaker is putting away what?
→ die Bohrmaschine

Since Bohrmaschine is feminine, the nominative and accusative singular look the same:

• Nominative: die Bohrmaschine
• Accusative: die Bohrmaschine

So the case is accusative, even though the form does not change.

Because German very often uses the present tense to talk about near-future or intended actions, especially when the context already makes the time clear.

Here the future meaning is obvious from the situation:

• Bevor wir gehen clearly refers to what happens before leaving
• will ... lüften expresses intention

So German does not need a special future form here. This is completely normal and very common.