Kad dođe kući, prvo otkopča kaput, a onda pokuša odvezati mokre vezice.

Croatian often leaves out subject pronouns because the verb ending already shows the person.

Here, dođe, otkopča, and pokuša are all 3rd person singular, so the sentence naturally means he/she does these actions. The exact gender depends on context. You would only add on or ona if you wanted emphasis, contrast, or extra clarity.

Because dođe is a perfective verb form, and it focuses on the action as a completed point: when he/she gets home / once he/she arrives home.

With kad, Croatian very often uses a perfective present form like dođe to talk about:

• a completed future point
• or a repeated sequence, as in whenever he/she gets home

Dolazi is imperfective, and it would sound more like is coming home or refer to an ongoing/regular process rather than the moment of arrival.

So:

• kad dođe kući = when he/she gets home
• kad dolazi kući = more like when he/she is coming home or when he/she comes home regularly, depending on context

Kući is the normal form used with verbs of movement to mean home.

So Croatian says:

• ići kući = to go home
• doći kući = to come home
• vratiti se kući = to return home

You do not say doći kuća.

A useful contrast is:

• kući = home / to home
• kod kuće = at home
• u kuću = into the house

So dođe kući means gets home / comes home, not specifically enters the house as a building.

Otkopča comes from otkopčati, which means to unfasten.

With clothing, that can mean:

• unbutton
• unzip
• undo
• unbuckle

depending on what kind of fastening the item has.

So otkopča kaput means something like he/she unfastens the coat. In natural English, that might be unbuttons the coat or unzips the coat, depending on the coat.

Both kaput and vezice are direct objects, so they are in the accusative case.

But in Croatian, some nouns have the same form in nominative and accusative.

That is what happens here:

• kaput is masculine inanimate singular, so nominative and accusative are both kaput
• vezice is plural inanimate, and here the accusative plural is also vezice

So the case is changing grammatically, even though the form does not look different.

Because pokušati is commonly followed by an infinitive in standard Croatian.

So:

• pokušati odvezati = to try to untie

This is very natural and standard.

Also, pokuša is perfective, so it suggests he/she gives it a try or tries as a single step in the sequence. If you used pokušava, that would sound more ongoing or repeated: is trying / keeps trying.

You may sometimes hear da-constructions in speech, but in standard Croatian, after pokušati, the infinitive is usually the best choice.

Odvezati comes from vezati, meaning to tie. So odvezati means to untie or to undo.

Vezice literally means laces, ties, or little strings, depending on context. In this sentence, because someone comes home, unfastens a coat, and then tries to untie wet laces, the natural meaning is shoelaces.

So odvezati mokre vezice is most naturally understood as to untie wet shoelaces.

Because adjectives in Croatian must agree with the noun in:

• gender
• number
• case

Here, vezice is:

• feminine
• plural
• accusative (as the object)

So the adjective also has to be feminine plural accusative, which gives mokre.

That is why you get:

• mokre vezice = wet laces

They organize the actions into a clear sequence.

• prvo = first
• onda = then
• a onda = and then / then

The a here links the second step to the first one very naturally. It is a very common way to move the story forward in Croatian.

So the sentence has this structure:

• Kad dođe kući = when he/she gets home
• prvo otkopča kaput = first unfastens the coat
• a onda pokuša odvezati mokre vezice = and then tries to untie the wet laces

It can work for either, depending on context.

Very often, a sentence like this is understood as a habitual sequence:

• Whenever he/she gets home, first... then...

But Croatian can also use the present in a vivid, story-like way to describe a single scene:

• He/she gets home, first does this, then does that

Without more context, the habitual reading is especially natural because of kad dođe kući.