Trebalo bi da upakuješ poklon papirom za uvijanje.

Trebalo bi da is a very common Serbian way to express should / ought to.

So:

• Trebalo bi da upakuješ... = You should wrap...

It sounds like advice, recommendation, or mild obligation, not a strict command.

A rough breakdown:

• trebalo = literally something like it would be necessary / it should
• bi = a conditional particle, often giving the sense of would
• da = introduces the following clause

As a whole, it works as one expression: should.

Both can be used, but they are slightly different in tone.

• Treba da upakuješ poklon. = You need to / should wrap the gift.
• Trebalo bi da upakuješ poklon. = You should wrap the gift.

The version with trebalo bi da is usually:

• softer
• more polite
• less direct
• more like advice than obligation

Also, trebalo is in the neuter singular because this is an impersonal construction. It does not agree with you the way an English adjective would.

Upakuješ is the 2nd person singular present tense form of the perfective verb upakovati / upakovati (depending on the variant).

Here it means:

• you wrap / you pack
• but in context: you should wrap

Because Serbian often uses the present tense after da, even when English would use an infinitive:

• da upakuješ = to wrap / that you wrap

So the structure is:

• Trebalo bi da upakuješ...
• literally: It would be advisable that you wrap...

That is normal Serbian grammar.

After da, Serbian usually uses a finite verb form rather than an infinitive. So where English says:

• You should wrap the gift

Serbian says something closer to:

• You should that-you-wrap the gift

Of course, that is not how you should translate it literally in normal English, but it helps explain the grammar.

So:

• da upakuješ = a clause with a present-tense verb
• English equivalent = to wrap or wrap

Poklon is in the accusative singular, but for this noun the accusative looks the same as the nominative because poklon is an inanimate masculine noun.

So:

• nominative: poklon = gift
• accusative: poklon = gift (same form)

It is accusative because it is the direct object of upakuješ:

• upakuješ poklon = wrap the gift

If the noun were animate masculine, the accusative would usually look different.

Papirom is the instrumental singular of papir (paper).

It is used here because Serbian often uses the instrumental case to show the means/material/tool used to do something.

So:

• papirom = with paper / using paper

In this sentence:

• upakuješ poklon papirom za uvijanje
• literally: wrap the gift with wrapping paper

This is why there is no extra word like with in Serbian—the instrumental case already carries that function.

Because the instrumental case can be used without a preposition to mean with / by means of.

For example:

• sečem nožem = I cut with a knife
• pišem olovkom = I write with a pencil
• upakovati papirom = to wrap with paper

So papirom by itself already means something like with paper.

Be careful, though: instrumental is also used with some prepositions, but here it is used without one.

Za uvijanje literally means for wrapping.

Breakdown:

• za = for
• uvijanje = a verbal noun, something like wrapping

So:

• papir za uvijanje = paper for wrapping
• in natural English: wrapping paper

This is a very common Serbian pattern:

• something + za + verbal noun
• meaning something for doing X

Yes. In this sentence, papirom za uvijanje goes together and means:

• with wrapping paper

More literally:

• with paper for wrapping

So the structure is:

• upakuješ = wrap
• poklon = the gift
• papirom za uvijanje = with wrapping paper

Yes, often you can.

For gifts, Serbian commonly uses verbs like:

• upakovati = to pack / wrap
• umotati = to wrap up

So:

• Trebalo bi da upakuješ poklon...
• Trebalo bi da umotaš poklon...

Both can work, though the nuance may shift slightly depending on context.

Very roughly:

• upakovati can sound a bit broader: pack / package / wrap
• umotati focuses more directly on wrapping something around the object

For a present, both are natural.

No, not exactly. It is more like advice or a recommendation.

• Trebalo bi da... = You should...
• A direct command would be stronger, for example:
  • Upakuj poklon papirom za uvijanje. = Wrap the gift in wrapping paper.

So the original sentence sounds softer and less forceful.

Yes, Serbian word order is fairly flexible.

The basic sentence is:

• Trebalo bi da upakuješ poklon papirom za uvijanje.

But depending on emphasis, you might also hear variations like:

• Poklon bi trebalo da upakuješ papirom za uvijanje.
• Trebalo bi da poklon upakuješ papirom za uvijanje.

The meaning stays basically the same, but the focus may shift slightly.

The original order is natural and neutral.

It is understandable and grammatical, but depending on region or speaker, other expressions may also be common.

You may hear:

• papir za uvijanje
• ukrasni papir
• papir za pakovanje
• ukrasni papir za poklone

So yes, papir za uvijanje works, but Serbian can use a few different expressions depending on exactly what kind of paper is meant.

Here are the basic forms:

• trebalo bi da → expression meaning should
• upakuješ → dictionary form: upakovati / upakovati
• poklon → dictionary form: poklon
• papirom → dictionary form: papir
• za → for
• uvijanje → dictionary form: uvijanje; related to the verb uvijati / uviti

So if you were looking these up, those are the forms you would search for.