Po turnieju każdy zawodnik i każda zawodniczka dostaną wodę i kanapkę.

Because po means after here, and in this meaning it requires the locative case.

• dictionary form: turniej
• after po: po turnieju

So po turnieju = after the tournament.

A useful extra note: po can take different cases with different meanings. For example, po wodę means to get water / for water, which is a different pattern.

This literally means each male competitor and each female competitor.

Polish adjectives and pronouns must agree with the gender of the noun:

• każdy goes with a masculine noun: każdy zawodnik
• każda goes with a feminine noun: każda zawodniczka

The sentence explicitly includes both men and women. It is more specific than just using one general group word.

Because Polish often uses singular forms to express each individual person.

So:

• każdy zawodnik = each male competitor
• każda zawodniczka = each female competitor

This is a distributive idea: the sentence talks about what happens to every person one by one, even though the whole group is plural in meaning.

Because the full subject is made of two parts joined by i:

• każdy zawodnik
• każda zawodniczka

Together, they form a plural subject, so the verb must be plural:

• dostaną = they will get

If you had only one part, you would use singular:

• Każdy zawodnik dostanie wodę i kanapkę.

Dostaną means they will get / receive.

It comes from the verb dostać, which is a perfective verb. In Polish, perfective verbs use present-looking forms to talk about the future.

So:

• dostaną is grammatically present-shaped
• but its meaning is future

That is why it translates as will get, not get.

Because they are direct objects, so they appear in the accusative case.

Basic forms:

• woda
• kanapka

Accusative singular:

• wodę
• kanapkę

For many feminine nouns ending in -a, the accusative singular changes -a to -ę.

So:

• woda → wodę
• kanapka → kanapkę

Yes, that is the natural meaning here.

Because the subject is each competitor, the sentence is understood distributively: every participant will receive water and a sandwich.

Polish does not need to repeat one here. If you wanted to be extra explicit, you could add words like:

• po jednej kanapce = one sandwich each

But in this sentence, the meaning is already clear without that.

They are gendered nouns:

• zawodnik = a male competitor / contestant / athlete
• zawodniczka = a female competitor / contestant / athlete

In a sports context, zawodnik / zawodniczka usually means someone taking part in a competition, not necessarily specifically a player in the narrow English sense.

Yes. Polish word order is fairly flexible.

This sentence starts with Po turnieju to set the time first:

• Po turnieju każdy zawodnik i każda zawodniczka dostaną wodę i kanapkę.

You could also say:

• Każdy zawodnik i każda zawodniczka dostaną wodę i kanapkę po turnieju.

The basic meaning stays the same, but the emphasis changes a little. The original version highlights when this happens right away.

Because Polish does not have articles like English the and a/an.

So Polish simply says:

• turnieju
• zawodnik
• wodę
• kanapkę

Whether English needs the, a, or no article at all depends on context and translation, not on a separate Polish word.