Na zid ću objesiti fotografiju mora, a iznad stola malu lampu.

Croatian normally has no articles. So zid, stol, fotografija, and lampa can mean a wall / the wall, a table / the table, and so on, depending on context.

If Croatian needs to be more specific, it can use other words, such as:

• taj zid = that wall
• jedna lampa = a certain / one lamp

But in an ordinary sentence like this, no article is needed.

Because na changes case depending on whether you mean movement toward a place or location in a place.

• na + accusative = movement onto/toward something
• na + locative = being on something

Here the verb objesiti means to hang up, so the idea is movement/result: putting the photograph onto the wall. That is why you get na zid.

Compare:

• Objesit ću fotografiju na zid. = I’ll hang the photograph on the wall.
• Fotografija je na zidu. = The photograph is on the wall.

Because the preposition iznad takes the genitive case.

So:

• stol → nominative
• stola → genitive

That gives iznad stola = above the table.

Unlike na, iznad does not switch here between accusative and locative. It simply governs the genitive:

• iznad kuće = above the house
• iznad grada = above the city
• iznad stola = above the table

Because fotografiju is the direct object of objesiti.

The verb objesiti answers what will I hang up?
Answer: fotografiju mora.

Since it is a feminine singular direct object, fotografija changes to the accusative singular:

• fotografija → nominative
• fotografiju → accusative

Because mora is the genitive singular of more and it means of the sea.

Croatian often uses a noun + genitive structure where English uses of:

• fotografija mora = photograph of the sea
• boja neba = color of the sky
• vrata kuće = door of the house

So fotografiju mora literally means a photograph of the sea.

Because this is also a direct object, so it has to be in the accusative singular.

Base form:

• mala lampa = nominative

Object form:

• malu lampu = accusative

Both words change because the adjective must agree with the noun in gender, number, and case:

• mala → malu
• lampa → lampu

Because ću is a clitic, and Croatian clitics usually go in the second position of the clause.

In this sentence, the first unit is Na zid, so ću comes right after it:

• Na zid ću objesiti...

This is very normal Croatian word order.

If the infinitive comes first, standard Croatian usually prefers the contracted written form:

• Objesit ću fotografiju...

rather than Objesiti ću fotografiju...

Because Croatian often leaves out repeated words when they are already clear from context. This is called ellipsis.

The full version would be:

• Na zid ću objesiti fotografiju mora, a iznad stola ću objesiti malu lampu.

But since ću objesiti is the same idea again, it can be omitted in the second part:

• ... a iznad stola malu lampu.

Even though the verb is omitted, malu lampu still stays in the accusative because it is understood as the object of objesiti.

Because Croatian word order is fairly flexible, and this order puts the focus on where each thing will go.

The sentence is organized like this:

• on the wall → the photograph
• above the table → the lamp

That creates a neat parallel structure and makes the placement sound important.

A different word order is also possible, for example:

• Fotografiju mora ću objesiti na zid, a malu lampu iznad stola.

That is also grammatical, but the emphasis is slightly different.

Here a links two parallel parts of the sentence. It often translates as and, but it can also have a slight contrastive or balancing feel:

• this goes here, and that goes there

So in this sentence, a is not just simple addition; it helps contrast the two placements.

The comma is normal because a is joining two coordinated clause-like parts:

• Na zid ću objesiti fotografiju mora, a iznad stola malu lampu.

Because objesiti is a perfective verb, and that fits the meaning of a single completed future action.

The idea is not just I will be hanging in a general or ongoing sense. The idea is:

• I will hang it up, and then it will be in place.

That completed-result meaning is exactly what perfective verbs are good at.

So ću objesiti sounds natural for a specific plan like this.