Προτού πάω στο υποκατάστημα της τράπεζας, κοιτάω αν έχω μαζί μου όλα τα δικαιολογητικά.

Προτού means before.

In modern Greek, it is correct and natural, but it sounds a bit more formal or polished than πριν. In everyday conversation, many speakers would more often say:

Πριν πάω στο υποκατάστημα...

So:

• προτού = before
• πριν = before, usually more common in everyday speech

Both are good Greek.

After προτού, Greek normally uses a verb form equivalent to the subjunctive-type dependent form, not an infinitive like English.

So Greek says:

• Προτού πάω... = before I go...

rather than something like before going.

A learner may expect πηγαίνω, but πάω is extremely common and natural for go. In this sentence, it refers to the act of going to the branch, so πάω works very well.

You may also see:

• Πριν πάω...
• Προτού να πάω...

but Προτού πάω... is perfectly normal.

Because the sentence describes a habit or usual procedure.

It means something like:

• Before I go to the bank branch, I check whether I have all the documents with me.

This is the same idea as English habitual present:

• Before I leave, I check...

So the present tense here does not necessarily mean "right now." It means this is what I generally do.

If you wanted a one-time future meaning, Greek could use future forms, for example:

• Προτού πάω..., θα κοιτάξω... = Before I go..., I will check...

Literally, κοιτάω means look or watch, but in this sentence it means check or make sure.

So here:

• κοιτάω αν έχω... = I check whether I have...

This is very common Greek. Greek often uses κοιτάω in situations where English would say:

• check
• see
• make sure

A slightly more formal alternative would be ελέγχω:

• ελέγχω αν έχω μαζί μου...

But κοιτάω sounds very natural in everyday speech.

This part breaks down like this:

• στο = σε + το = to/in the
• υποκατάστημα = branch
• της τράπεζας = of the bank / the bank’s

So literally:

• στο υποκατάστημα της τράπεζας = to the branch of the bank

A few useful grammar points:

1. στο is the contraction of σε το.
2. After σε, Greek uses the accusative.
3. της τράπεζας is in the genitive, because it means of the bank.

So this is a very standard structure:

• το υποκατάστημα της τράπεζας
• the bank branch

Here αν means whether, not a real condition.

So:

• κοιτάω αν έχω μαζί μου...
• I check whether I have with me...

English often uses if and whether in similar sentences:

• I check if I have...
• I check whether I have...

Greek uses αν for that kind of indirect yes/no question.

So this is not:

• If I have the documents, then...

It is:

• I check whether I have the documents.

Έχω μαζί μου literally means I have with me.

It is a very common Greek way to say:

• I have it with me
• I’m carrying it
• I have it on me

So:

• έχω μαζί μου όλα τα δικαιολογητικά
• I have all the documents with me

The words are:

• μαζί = together / with
• μου = me

In this expression, μαζί μου means with me.

You can change the pronoun:

• μαζί σου = with you
• μαζί του = with him
• μαζί της = with her
• μαζί μας = with us

Yes, it is related historically, and that can confuse English speakers.

Δικαιολογητικά in everyday administrative Greek usually means:

• supporting documents
• required paperwork
• official documents you need to present

So in a bank context, it means things like:

• ID
• proof of address
• tax documents
• forms

It does not usually mean justifications in this kind of sentence.

So:

• όλα τα δικαιολογητικά = all the required documents / all the paperwork

Because with όλος meaning all, Greek normally uses the article with countable nouns.

So the standard pattern is:

• όλα τα δικαιολογητικά = all the documents

Compare:

• όλα τα βιβλία = all the books
• όλες οι μέρες = all the days
• όλοι οι άνθρωποι = all the people

So όλα δικαιολογητικά would sound incomplete or unnatural in standard Greek.

Here:

• όλα agrees with δικαιολογητικά
• both are neuter plural

No, Greek word order is more flexible than English word order.

The given order is natural and clear:

• κοιτάω αν έχω μαζί μου όλα τα δικαιολογητικά

But Greek could also move parts around for emphasis, for example:

• κοιτάω αν έχω όλα τα δικαιολογητικά μαζί μου

This would still mean the same thing.

The version in your sentence sounds very natural because μαζί μου comes before the object and smoothly sets up the idea of having them on me.

So the order is not completely fixed, but the original sentence is a very normal choice.