Ako bude gužva, nećemo naći mjesto u tramvaju.

In Croatian, when ako introduces a future condition, the language normally uses bude / budem / budeš... rather than će biti.

So:

• Ako bude gužva = If it’s crowded / If there is a crowd
• not normally Ako će biti gužva

Learners often see this explained as a use of future II or as the special future form used in subordinate clauses after words like ako, kad, čim, etc.

So the pattern is very common:

• Ako bude vremena, doći ću.
• Ako budeš mogao, nazovi me.

Gužva is a very common Croatian noun meaning something like:

• crowd
• rush
• congestion
• packed conditions

In this sentence, it means the tram is crowded, busy, or too full of people.

So Ako bude gužva suggests:

• there will be a lot of people
• it may be hard to get in comfortably
• it may be hard to find space or a seat

Nećemo naći means we will not find.

The future negative in Croatian is formed with:

• neću
• nećeš
• neće
• nećemo
• nećete
• neće

plus the infinitive.

So:

• naći ćemo = we will find
• nećemo naći = we will not find

A useful thing to notice is that these negative future forms are written as one word:

• neću, not ne ću
• nećemo, not ne ćemo

Because naći is a perfective verb, and here Croatian is talking about a single completed result: whether we succeed in finding a place or not.

• naći = to find successfully, as a completed event
• nalaziti = to be finding / to find repeatedly / habitually

In this sentence, the idea is:

• Will we manage to find a place?
• No, we won’t.

That is why naći is the natural choice.

Croatian often leaves out subject pronouns because the verb ending already tells you who the subject is.

Here, nećemo already means we will not, because -mo marks we.

So:

• Nećemo naći mjesto = We won’t find a place
• Mi nećemo naći mjesto = also possible, but more emphatic

You would add mi only if you want contrast or emphasis, for example:

• Oni će možda naći mjesto, ali mi nećemo. = They may find a place, but we won’t.

It can mean all of those depending on context.

In u tramvaju, mjesto usually means:

• a place
• room
• space
• sometimes a seat

So nećemo naći mjesto u tramvaju can mean:

• we won’t find room in the tram
• we won’t find a place to stand or sit
• possibly we won’t find a seat

If you want to say specifically seat, Croatian often uses sjedalo. But mjesto is broader and very natural here.

It is the accusative singular, because it is the direct object of naći.

We are finding what? → mjesto

A detail that can confuse learners: mjesto is a neuter noun, and in the singular its nominative and accusative forms look the same.

So even though it is accusative here, the form still stays mjesto.

U tramvaju means in the tram / on the tram, and tramvaju is in the locative singular.

Croatian uses u + locative for location:

• u kući = in the house
• u školi = at school
• u tramvaju = in/on the tram

This is one place where English and Croatian differ. English often says on the tram, but Croatian says u tramvaju.

Also compare:

• u tramvaju = inside the tram, located there
• u tramvaj = into the tram, motion toward the inside

For example:

• Sjedimo u tramvaju. = We are sitting on the tram.
• Ulazimo u tramvaj. = We are getting onto the tram.

Because Ako bude gužva is a subordinate conditional clause placed before the main clause.

So the sentence is structured like this:

• Ako bude gužva, = if it’s crowded
• nećemo naći mjesto u tramvaju. = we won’t find a place in the tram

When the ako clause comes first, the comma separates it from the main clause.

Yes. Croatian word order is fairly flexible.

A very natural alternative is:

• Nećemo naći mjesto u tramvaju ako bude gužva.

This means the same thing.

The version with the ako clause first often sounds a bit more natural when setting up the condition first:

• Ako bude gužva, nećemo naći mjesto u tramvaju.

Croatian can also change word order for emphasis, but the original sentence is a very normal, neutral way to say it.

This is a very useful distinction.

• Ako bude gužva = If it’s crowded in a future situation
• Ako je gužva = If it’s crowded now, or whenever it is crowded in general

In your sentence, the speaker is talking about a future possibility, so bude is the normal choice.

Compare:

• Ako bude gužva, ići ćemo pješice. = If it’s crowded, we’ll go on foot.
  future event

• Ako je gužva, obično čekam sljedeći tramvaj. = If it’s crowded, I usually wait for the next tram.
  general/habitual meaning

Yes, tramvaj is a masculine noun.

Its basic form is:

• tramvaj = nominative singular

After u when expressing location, it goes into the locative singular:

• u tramvaju

So this is just a regular case change:

• tramvaj → tramvaju

You will see the same kind of pattern with other masculine nouns too.