Při výběru hotovosti potřebujete PIN a zaplatíte poplatek.

Here při means something like during, when, or in the course of.

So Při výběru hotovosti is literally during the withdrawal of cash, and in natural English it corresponds to when withdrawing cash or for a cash withdrawal.

A very important grammar point: při takes the locative case.

Because it is the locative singular form of výběr.

• dictionary form: výběr = withdrawal, selection
• after při: při výběru

So the ending changes because při requires the locative:

• výběr → při výběru

Because hotovosti is the genitive singular form of hotovost.

In the phrase výběr hotovosti, Czech uses the genitive to show withdrawal of what?
So:

• výběr = withdrawal
• hotovosti = of cash

This is very similar to English withdrawal of cash, even though English often says cash withdrawal instead.

Yes, very natural—especially in formal or written contexts such as banking, ATMs, instructions, or notices.

It is slightly more formal and noun-based than a fully verbal version. Czech often likes this kind of structure in official language:

• Při výběru hotovosti... = during cash withdrawal / when withdrawing cash

You may also see more verbal phrasing in other contexts, but this version is completely normal.

Potřebujete is the 2nd person plural form of potřebovat.

It can mean:

• you (plural) need
• you (formal singular) need

In public signs, instructions, and customer messages, Czech usually addresses the reader with this polite/general you form. So even if the sentence is aimed at one customer, potřebujete is normal.

Also, Czech often omits the pronoun vy because the verb ending already shows who the subject is.

Because PIN is treated as an indeclinable abbreviation in everyday use.

Even though it is the object of potřebujete and would logically be in the accusative, its form stays the same:

• potřebujete PIN

Many abbreviations and foreign-looking items behave this way in Czech. In practice, learners can usually just remember PIN as unchanged.

Because zaplatíte comes from the perfective verb zaplatit, while platíte comes from the imperfective verb platit.

The difference is roughly:

• platit = to pay, be paying, pay regularly
• zaplatit = to pay successfully / to complete a payment

In this sentence, the idea is that one specific payment will happen as part of the transaction, so zaplatíte is very natural.

This is a very common Czech pattern.

Perfective verbs do not have a true present meaning. Their present-looking forms usually refer to the future. So:

• zaplatíte = you will pay

In instructions, rules, and notices, Czech often uses this form for things that generally happen in a situation:

• Při výběru hotovosti ... zaplatíte poplatek.
• When you withdraw cash, you will pay a fee.

So even though it is a general statement, the idea is still each time this happens, the payment will occur.

Because they express two different kinds of meaning.

• potřebujete uses an imperfective verb and gives a general present fact: you need a PIN
• zaplatíte uses a perfective verb and describes a completed result in that situation: you will pay a fee

So the sentence is not inconsistent. It is combining:

1. a general requirement
2. a resulting action/outcome

That is very normal in Czech.

Poplatek is in the accusative singular, because it is the direct object of zaplatíte.

The useful thing here is that for many masculine inanimate nouns, the accusative singular looks the same as the nominative singular:

• nominative: poplatek
• accusative: poplatek

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

Because Czech has no articles.

So Czech does not normally distinguish between:

• a PIN
• the PIN

or between:

• a fee
• the fee

The context tells you which meaning is intended. In this sentence, English naturally adds articles, but Czech simply does not need them.

Yes, Czech word order is fairly flexible, but the given order is natural and neutral for an instruction or notice.

Starting with Při výběru hotovosti sets the situation first:

• During cash withdrawal / When withdrawing cash...

Then the sentence gives the two facts:

• potřebujete PIN
• zaplatíte poplatek

A different word order is possible, but it would usually change the emphasis slightly. The original version sounds like standard banking or ATM language.