Ovdje vidim broj okvira, lokot i zaštitni lanac.

Because Croatian often drops subject pronouns when the verb already shows who is doing the action.

Vidim means I see:

• vid- = the verb stem
• -im = 1st person singular

So Ovdje vidim... already means Here I see...
You could add ja for emphasis — Ja ovdje vidim... — but it is not necessary in a neutral sentence.

Ovdje means here, and Croatian word order is fairly flexible. Putting it first highlights the location.

So:

• Ovdje vidim broj okvira... = emphasis on here
• Vidim ovdje broj okvira... = also possible, but the focus feels a bit different

Starting with ovdje is natural if the speaker is pointing out what can be seen in this place.

Because Croatian often uses the genitive after a noun like number, part, name, and similar expressions.

So:

• broj = number
• okvira = genitive form of okvir

This literally works like number of the frame.

This pattern is very common:

• broj telefona = phone number
• ime grada = name of the city
• vrata auta = the car door / door of the car

They are direct objects of vidim, so they are in the accusative.

However, all three nouns here are masculine inanimate, and in Croatian the accusative singular of masculine inanimate nouns is usually the same as the nominative singular.

So:

• broj → accusative broj
• lokot → accusative lokot
• lanac → accusative lanac

That is why they do not visibly change.

Because the adjective has to agree with the noun it describes.

Here:

• lanac = masculine singular, inanimate
• so zaštitni must also be masculine singular accusative

For masculine inanimate nouns, the accusative singular adjective form is the same as the nominative singular form, so you get:

• zaštitni lanac

If the noun were different, the adjective would change too:

• zaštitna vrata = protective door(s)
• zaštitno staklo = protective glass

Croatian does not have articles like English the and a/an.

So a noun like lokot can mean:

• a lock
• the lock

The exact meaning depends on context.

Croatian usually shows definiteness through:

• context
• word order
• demonstratives such as ovaj, taj, onaj when needed

For example:

• Vidim lokot. = I see a/the lock.
• Vidim taj lokot. = I see that lock.

Here it is understood as genitive singular: of the frame.

The form okvira can be ambiguous in isolation, because Croatian case endings sometimes overlap. But in broj okvira, the normal meaning is frame number, so learners should understand it as singular here.

If the meaning were plural, the context would usually make that clear.

Because this is a list of three things:

• broj okvira
• lokot
• zaštitni lanac

In Croatian, as in English, you normally separate earlier items in a list with commas, but you usually do not put a comma before the final i (and).

So:

• broj okvira, lokot i zaštitni lanac

That is standard punctuation.

Yes. Croatian word order is flexible, although different orders sound more or less natural depending on emphasis.

For example, these are possible:

• Ovdje vidim broj okvira, lokot i zaštitni lanac.
• Vidim ovdje broj okvira, lokot i zaštitni lanac.
• Broj okvira, lokot i zaštitni lanac vidim ovdje.

They all express roughly the same basic idea, but the focus changes:

• sentence-initial ovdje emphasizes the place
• sentence-initial broj okvira, lokot i zaštitni lanac emphasizes the things seen

The original version is a natural neutral choice if the speaker wants to begin with here.