Mientras tanto, la empleada organiza la fila frente a la taquilla.

Yes. Mientras tanto is a very common fixed expression meaning meanwhile or in the meantime.

A few useful notes:

• mientras by itself often means while
• mientras tanto works together as an expression meaning meanwhile
• It is often used at the beginning of a sentence to set the scene

Example:

• Mientras tanto, la empleada organiza la fila... = Meanwhile, the employee organizes the line...

The comma after it is very natural when it appears at the start of a sentence.

La empleada means the female employee.

Here is the pattern:

• el empleado = the male employee
• la empleada = the female employee

The noun changes ending from -o to -a to match gender, and the article changes too:

• el for masculine singular
• la for feminine singular

So la empleada tells you the worker is female.

In Spanish, the simple present tense often does the job that English uses the present progressive for.

So:

• organiza can mean organizes or is organizing, depending on context

In this sentence, it most naturally means:

• the employee is organizing the line

Spanish does not need está organizando every time an action is happening right now. The simple present is very common for ongoing actions, especially in descriptions and narration.

Organiza is the third person singular present tense of organizar.

Conjugation:

• yo organizo = I organize
• tú organizas = you organize
• él / ella / usted organiza = he / she / you organize(s)

Since the subject is la empleada = she/the employee, organiza is the correct form.

Spanish often uses the definite article more than English does.

Here, la fila means the line or the queue. It suggests a specific line that is already understood in the situation, such as the line of customers at a ticket window.

Even when English might sometimes say organizes people into a line, Spanish may naturally say organiza la fila.

So this is idiomatic Spanish, not a word-for-word copy of English structure.

Fila means line, row, or queue, depending on context.

In this sentence, it means the line of people waiting.

You may also hear cola for line/queue in many places. Both can refer to a waiting line, but usage varies by region.

Very generally:

• fila often sounds a bit more neutral or formal
• cola is also very common in many countries for a line of people

So la fila here is perfectly natural for the line.

Frente a means in front of or facing.

In this sentence:

• la fila frente a la taquilla = the line in front of the ticket window / box office

It is a very common prepositional expression.

Compare:

• frente a la escuela = in front of the school
• frente al banco = in front of the bank

Notice that a + el = al, but with la there is no contraction:

• frente al teatro
• frente a la taquilla

In this context, taquilla usually means something like:

• ticket window
• ticket booth
• box office

It refers to the place where tickets are sold.

A useful caution:

• The exact everyday meaning of taquilla can vary by country
• In some places, related words may refer to slightly different things, such as a booth or even a locker in other contexts

But in a sentence with la fila frente a la taquilla, the meaning is very naturally the line in front of the ticket window/box office.

Yes. Organizar la fila is natural and means the employee is:

• arranging the line
• managing the queue
• getting people into order

It does not necessarily mean she is physically moving objects around. It can mean she is directing people so the line is orderly.

Other possible verbs in similar contexts could be:

• ordenar la fila = to put the line in order
• controlar la fila = to control/manage the line

But organiza la fila sounds completely normal.

Because it describes where the line is.

The structure is:

• la empleada = subject
• organiza = verb
• la fila = direct object
• frente a la taquilla = phrase describing the line’s location

So the sentence flows as:

• Meanwhile, the employee organizes the line in front of the ticket window.

Spanish often places location phrases after the noun or after the main object in a very natural way.

In many varieties of Spanish, yes, you may hear enfrente de or en frente de used with a similar meaning.

However:

• frente a is very standard and widely accepted
• enfrente de / en frente de is also common in many regions, but usage can vary

For a learner, frente a is a safe and useful choice.

So:

• frente a la taquilla = excellent, standard option

Only the subject would need to change:

• Mientras tanto, el empleado organiza la fila frente a la taquilla.

The rest stays the same because:

• organiza still matches a third-person singular subject
• fila is still feminine: la fila
• taquilla is still feminine: la taquilla

So the only difference is:

• la empleada → el empleado