Poslije posla prvo završim obaveze kod kuće, a tek onda se odmaram.

Because poslije means after and it requires the genitive case.

• basic noun: posao = work, job
• genitive singular: posla

So:

• poslije posla = after work

This is very common in Croatian: certain prepositions force a specific case, and poslije is one of them.

Prvo means first or first of all.

In this sentence, it works as an adverb, telling you the order of actions:

• prvo završim obaveze = I first finish my tasks/chores

Other common options you may also see are:

• najprije = first, first of all
• prvo = first

They are often interchangeable in everyday speech.

This is a question about verb aspect, which is very important in Croatian.

• završiti = to finish (perfective)
• završavati = to be finishing / to finish repeatedly or as a process (imperfective)

Here, završim is used because the speaker is talking about a completed step before the next action happens:

• first I finish the chores
• only then I rest

So the perfective verb fits the idea of completion.

A useful way to feel the difference:

• završim obaveze = I get the chores done / I finish them
• završavam obaveze = I am finishing the chores / I tend to be finishing them / the process is in progress

In a sequence like this, završim sounds very natural because it emphasizes that the chores are completed before resting starts.

That is a very good observation.

In Croatian, a perfective present like završim usually does not mean I am finishing right now. However, it is often used in sequences, routines, and narrative-style descriptions where the speaker presents actions as complete steps.

So this sentence is not really about an action happening at this exact second. It is more like:

• After work, I first finish the chores at home, and only then I rest.

That is a habitual sequence or routine, and Croatian often uses the perfective present naturally in that kind of description.

Obaveze is the plural of obaveza, meaning:

• obligations
• duties
• tasks
• chores

In this sentence, the most natural English translation is probably chores or tasks, because of kod kuće.

So:

• završim obaveze kod kuće = I finish my chores/tasks at home

One important note: in standard Croatian, you will very often see obveze instead of obaveze.
So for a learner of Croatian, both are useful to recognize:

• obveze = standard Croatian form
• obaveze = very common in Bosnian/Serbian and widely understood

Croatian often leaves out possessive words like my, your, or his/her when the meaning is already clear from context.

So:

• završim obaveze kod kuće naturally suggests I finish my chores at home

If the speaker wanted to make it extra explicit, they could say:

• završim svoje obaveze kod kuće = I finish my chores at home

But in many everyday sentences, Croatian simply does not need the possessive if it is obvious.

Kod kuće is the normal idiomatic expression for at home.

So:

• kod kuće = at home

This is different from u kući, which means in the house or inside the house and focuses more on physical location inside the building.

Compare:

• Ostajem kod kuće. = I’m staying at home.
• On je u kući. = He is in the house.

In your sentence, kod kuće is the natural choice because it means at home in a general everyday sense.

This part adds emphasis to the sequence.

• a = and, but, while, whereas — here it links the second part and gives a mild contrast
• tek onda = only then

So:

• a tek onda se odmaram = and only then do I rest

The word tek is important because it emphasizes that resting happens only after the chores are done.

Compare:

• a onda se odmaram = and then I rest
• a tek onda se odmaram = and only then do I rest

So tek makes the sequence stronger and more deliberate.

The verb is odmarati se, which means to rest or to relax.

So se is part of the verb expression here. You learn it as:

• odmarati se = to rest
• odmaram se = I rest / I am resting

In this sentence, the word order is:

• a tek onda se odmaram

This happens because se is a clitic, and Croatian clitics usually go near the beginning of their clause, often after the first stressed word or phrase.

So after tek onda, you get:

• tek onda se odmaram

That is normal Croatian word order.

Yes, odmaram se is more natural and more common in everyday Croatian for I rest / I relax.

• odmarati se = to rest, relax
• relaksirati se = to relax, but it sounds more formal, borrowed, or less everyday in many contexts

So in a sentence about daily routine, odmaram se is the most natural choice.

It is understandable in Croatian, but it contains forms that may make a learner notice regional or standard differences.

Two likely things you may spot are:

• obaveze — standard Croatian often prefers obveze
• poslije — this is also used in Croatian, but you may also often see nakon in more formal standard language

A very standard-Croatian-looking version could be:

• Nakon posla prvo završim obveze kod kuće, a tek onda se odmaram.

But the original sentence is still perfectly understandable and natural in the broader BCMS language area.