Djeca su poslije dobila po dvije slike životinja za svoje sobe.

Because djeca means children, but grammatically it behaves differently from a regular masculine plural noun.

• Singular: dijete = child
• Plural: djeca = children

With djeca, Croatian uses the neuter plural form in adjectives and past participles, so:

• djeca su dobila
• not djeca su dobili

Compare:

• Muškarci su dobili = The men received
• Žene su dobile = The women received
• Djeca su dobila = The children received

So dobila agrees with djeca.

This is the normal Croatian perfect tense.

It is made with:

• the present tense of biti = to be
• plus the past participle

Here:

• su = they are / auxiliary for they
• dobila = received / got

Together, su dobila means received or got.

Croatian does not use have the way English does in the present perfect. So instead of something like they have received, Croatian uses they are received structurally, though in meaning it is just ordinary past tense.

Because su is a clitic, and Croatian clitics usually go in the second position in the sentence or clause.

So:

• Djeca su poslije dobila...

is normal because su comes right after the first element, djeca.

You will often see this with short words like:

• sam, si, je, smo, ste, su
• se
• ga, je, ih, etc.

Croatian word order is flexible, but clitic placement follows its own rules.

Poslije means later, afterwards, or after that.

In this sentence, it tells you when the children received the pictures:

• Djeca su poslije dobila... = The children later received...

A near equivalent is kasnije. In many contexts, poslije and kasnije are both possible, though poslije often has a slightly stronger sense of after something previously mentioned.

Po here is distributive. It means something like each or apiece.

So:

• po dvije slike = two pictures each

This is an important difference:

• dobile su dvije slike = they received two pictures
• dobile su po dvije slike = they each received two pictures

So the sentence does not mean there were only two pictures in total. It means each child got two.

Because slika is a feminine noun, and the number 2 changes form for gender.

• dva = masculine/neuter
• dvije = feminine

So:

• dva psa = two dogs
• dva sela = two villages
• dvije slike = two pictures

Since slika is feminine, dvije is required.

This is a very common Croatian structure: one noun followed by another noun in the genitive to show type, content, or association.

So:

• slike životinja = pictures of animals

Here:

• slike = pictures
• životinja = of animals

The word životinja is in the genitive plural here. It happens to look the same as the singular nominative form, but the meaning is plural because of the context.

Compare:

• slika životinje = a picture of an animal
• slike životinja = pictures of animals

Because Croatian normally uses svoj when the possessor is the same as the subject of the sentence.

Here, the subject is djeca, and the rooms belong to the same children, so:

• za svoje sobe = for their own rooms

This is the natural Croatian choice.

If you said njihove sobe, it could sound less natural here, and it can sometimes suggest someone else’s rooms, depending on context.

So a useful rule is:

• use svoj when the owner = the subject of the sentence

After za here, Croatian uses the accusative, because the meaning is for in the sense of intended for.

So:

• za svoje sobe = for their rooms

The form sobe here is accusative plural.

This may look identical to nominative plural, which is very common with feminine nouns.

Compare:

• soba = room
• sobe = rooms / the rooms
• za sobe = for rooms

Yes. Croatian word order is fairly flexible, and different orders can change emphasis.

For example, you could also say:

• Poslije su djeca dobila po dvije slike životinja za svoje sobe.

This still means the same thing, but it puts more focus on later/afterwards.

What usually stays important is the clitic placement:

• su still needs to be in the usual second-position area

So Croatian word order is flexible, but not random.