Po szkoleniu szefowa powiedziała, że rekrutacja skończy się dopiero w przyszłym tygodniu.

In Polish, a comma is normally required before że when it introduces a subordinate clause.

So:

Szefowa powiedziała, że... = The boss said that...

This is standard Polish punctuation. English is looser with that-clauses, but Polish usually keeps the comma here.

Po here means after, and in this meaning it takes the locative case.

• basic form: szkolenie = training, course, session
• locative singular: szkoleniu

So:

• po szkoleniu = after the training

This is a very common pattern:

• po pracy = after work
• po spotkaniu = after the meeting
• po obiedzie = after lunch

Szkolenie usually means training, a training session, or a training course.

Depending on context, English might translate it as:

• training
• the training session
• the workshop
• the course

So po szkoleniu does not have to mean only formal corporate training, but in this sentence that is probably the intended idea.

Szefowa means female boss/manager, while szef means male boss/manager.

So the sentence tells you the boss is female.

• szef = male boss
• szefowa = female boss

In modern Polish, szefowa is a normal, natural word.

Polish past tense agrees with the gender of the subject.

Because szefowa is feminine, the verb must also be feminine:

• powiedziała = she said
• powiedział = he said

So:

• Szefowa powiedziała = The female boss said
• Szef powiedział = The male boss said

This is one of the first big differences English speakers notice, because English past tense does not change for gender.

Polish often drops subject pronouns when the verb form already makes the subject clear.

Here, powiedziała already tells us the subject is:

• third person singular
• feminine
• past tense

And the noun szefowa is already stated anyway, so adding ona would be unnecessary.

Polish prefers:

• Szefowa powiedziała...

rather than:

• Szefowa ona powiedziała... — unnatural here

This is mainly about aspect and the type of action.

• powiedziała = she said, she made a completed statement
• mówiła = she was saying / she used to say / she spoke

In this sentence, the boss made one finished statement after the training, so powiedziała is the natural choice.

Compare:

• Po szkoleniu szefowa powiedziała, że...
  = After the training, the boss said that...

• Szefowa mówiła o rekrutacji przez godzinę.
  = The boss was talking about recruitment for an hour.

Że means that and introduces a content clause.

So:

• powiedziała, że... = said that...

Polish usually keeps że in places where English may drop that.

English:

• The boss said the recruitment would end next week.

Polish:

• Szefowa powiedziała, że rekrutacja skończy się w przyszłym tygodniu.

Leaving out że in standard Polish would sound wrong here.

Because rekrutacja is the subject of the subordinate clause:

• rekrutacja skończy się = recruitment will end

Subjects are normally in the nominative case, and rekrutacja is nominative singular.

So the second clause is built like this:

• rekrutacja = subject
• skończy się = verb

Because skończyć się is the verb meaning to end / to come to an end / to be over.

The się is important here.

Compare:

• skończyć coś = to finish something
• skończyć się = to end, to come to an end

So:

• Firma skończy rekrutację = The company will finish the recruitment process.
• Rekrutacja skończy się = The recruitment process will end.

English does not mark this difference with something like się, so this often feels strange at first.

Because it is a perfective verb.

In Polish, perfective verbs do not have a normal present tense with present meaning. Their present-looking forms usually refer to the future.

So:

• skończy się = will end

Its imperfective partner is kończyć się:

• kończy się = is ending / ends
• będzie się kończyć = will be ending

Here, the sentence means the recruitment will reach its end at some future point, so the perfective skończy się is exactly right.

Dopiero adds the idea of only, not until, or as late as.

So:

• skończy się w przyszłym tygodniu = it will end next week
• skończy się dopiero w przyszłym tygodniu = it will only end next week / it will not end until next week

This suggests delay or that the end is later than someone might expect.

Here w means in/during, and with this time expression it takes the locative case.

So:

• przyszły tydzień = next week (dictionary/basic form)
• w przyszłym tygodniu = in next week / next week

Forms:

• przyszły → przyszłym
• tydzień → tygodniu

This is a very common pattern:

• w tym roku = this year
• w przyszłym miesiącu = next month
• w zeszłym tygodniu = last week

They are similar, but not identical.

• w przyszłym tygodniu = next week, at some point during the next week
• za tydzień = in a week, one week from now

So in this sentence:

• skończy się w przyszłym tygodniu means the ending will happen sometime during next week.

If you said:

• skończy się za tydzień

that would mean it will end one week from now, which is a bit more exact and countdown-like.

Yes. Polish word order is flexible, and changing it often changes emphasis rather than the core meaning.

Original:

• Po szkoleniu szefowa powiedziała, że rekrutacja skończy się dopiero w przyszłym tygodniu.

Also possible:

• Szefowa powiedziała po szkoleniu, że rekrutacja skończy się dopiero w przyszłym tygodniu.
• Po szkoleniu szefowa powiedziała, że dopiero w przyszłym tygodniu skończy się rekrutacja.

These all mean roughly the same thing, but the focus shifts a little:

• fronting po szkoleniu highlights the time of speaking
• fronting dopiero w przyszłym tygodniu highlights the delay
• moving rekrutacja later can make the ending sound slightly more formal or dramatic

The original sentence is natural and neutral.

You would change both the noun and the past-tense verb:

• Po szkoleniu szef powiedział, że rekrutacja skończy się dopiero w przyszłym tygodniu.

Changes:

• szefowa → szef
• powiedziała → powiedział

The rest of the sentence stays the same.