Kad uđemo u galeriju, pogledat ćemo novu izložbu.

Kad means when.

Yes, kad and kada both mean when in this kind of sentence. The difference is mostly style and rhythm:

• kad = shorter, very common in everyday speech
• kada = a bit fuller/more formal, but still completely normal

So these are both fine:

• Kad uđemo u galeriju, pogledat ćemo novu izložbu.
• Kada uđemo u galeriju, pogledat ćemo novu izložbu.

There is no important difference in meaning here.

After kad meaning when, Croatian very often uses the present tense form of the verb, even when the meaning is future.

So:

• Kad uđemo... = When we enter / when we’ve entered...
• not usually Kad ćemo ući...

This is normal Croatian grammar. English learners often expect a future form because English refers to the future too, but Croatian commonly uses the present after time words like kad.

A similar pattern appears with other time conjunctions too, such as:

• Kad dođem, nazvat ću te. = When I arrive, I’ll call you.

Yes, uđemo is formally a present tense form.

It comes from the verb ući / ulaziti family, specifically the perfective verb ući (to enter, to go in). Its present-tense form can be used after kad to talk about a future completed action.

So in this sentence:

• Kad uđemo u galeriju...

the idea is:

• when we enter
• once we have entered

Because ući is perfective, it naturally points to a completed event: crossing the threshold and being inside.

That is why it fits well here.

This is mainly a question of aspect.

• ući / uđemo = perfective
• ulaziti / ulazimo = imperfective

Very roughly:

• uđemo focuses on the action as a whole, as a completed entry
• ulazimo focuses more on the process or repeated/general entering

In this sentence, uđemo is the natural choice because the meaning is:

• When we go in / once we get inside the gallery, we’ll look at the new exhibition.

If you said Kad ulazimo u galeriju..., it would sound less natural here, because that suggests an ongoing or habitual process rather than a single completed entry before the next action.

Because with u, Croatian distinguishes between:

• movement into a place → accusative
• location in a place → locative

So:

• u galeriju = into the gallery → movement, so accusative
• u galeriji = in the gallery → location, so locative

In your sentence, the verb uđemo means enter/go into, so movement is involved:

• Kad uđemo u galeriju...

That is why galeriju is correct.

Both are possible.

Croatian future tense can often be expressed in two common ways:

• pogledat ćemo
• ćemo pogledati

Both mean we will look at / we will see.

In standard Croatian, when the infinitive ends in -ti, that -ti is often dropped before the clitic forms of htjeti:

• pogledati + ćemo → pogledat ćemo

This is very common and standard.

So:

• Pogledat ćemo novu izložbu.
• Ćemo pogledati novu izložbu.

The first one is especially natural when the verb comes first in the clause.

Because this is the normal way Croatian writes many future-tense forms when the auxiliary comes after the infinitive stem.

The infinitive is:

• pogledati

But in this future construction, it becomes:

• pogledat ćemo

So the final -i is dropped.

A few more examples:

• vidjeti → vidjet ćemo
• napraviti → napravit ćemo
• kupiti → kupit ćemo

This is standard Croatian spelling.

In standard Croatian, it is written separately:

• pogledat ćemo

not as one word.

This is because ćemo is an auxiliary clitic, not a suffix attached as part of one written word.

A learner may notice forms written together elsewhere, especially in Serbian spelling conventions, but in standard Croatian you should write:

• gledat ću
• pogledat ćemo
• napravit ćeš

with a space.

Not exactly.

• gledati = to watch, to look at, often more ongoing
• pogledati = to take a look at, to see, to look at as a complete action

Here pogledat ćemo novu izložbu suggests a single complete action:

• we’ll go and see the new exhibition
• we’ll take a look at the new exhibition

That is why the perfective verb pogledati works well.

If you used gledati, it would sound more like watching or viewing as an ongoing activity.

It is accusative singular feminine.

Why? Because pogledati takes a direct object, and the direct object here is the new exhibition.

So:

• izložba = nominative
• izložbu = accusative

And the adjective has to agree with the noun:

• nova izložba = nominative
• novu izložbu = accusative

So the phrase changes together:

• nova izložba → novu izložbu

Yes, Croatian word order is fairly flexible.

Your sentence is completely natural:

• Kad uđemo u galeriju, pogledat ćemo novu izložbu.

But you could also say:

• Pogledat ćemo novu izložbu kad uđemo u galeriju.

This has the same basic meaning.

The version with Kad... first often sounds a little more like you are setting the time frame first: When we enter the gallery...

The second version starts with the main action: We’ll see the new exhibition when we enter the gallery.

Both are correct.

Because the sentence begins with a subordinate clause:

• Kad uđemo u galeriju = dependent clause
• pogledat ćemo novu izložbu = main clause

In Croatian, when this kind of time clause comes first, it is normally followed by a comma.

So:

• Kad uđemo u galeriju, pogledat ćemo novu izložbu.

If the main clause comes first, you also normally separate the clauses:

• Pogledat ćemo novu izložbu kad uđemo u galeriju.

In that order, the comma is often omitted.

A rough pronunciation guide:

• uđemo sounds approximately like OO-jemo, but with a soft sound in the middle

The letter đ is a soft consonant, somewhat similar to the j in judge, but softer and palatalized.

Very roughly:

• đ ≈ a soft j/dj sound

So:

• uđemo ≈ OO-djemo / OO-jemo (approximation only)

Also:

• lj in pogledat ćemo novu izložbu does not occur here, so that part is straightforward
• izložbu has ž, like the s in measure

These are only approximations, but they can help at first.