Uzela sam metlu, očistila kuhinju, oprala sudoper i obrisala pločice pokraj vrata.

Because the speaker is female.

In Croatian past tense, the main verb agrees with the speaker’s gender and number. So a woman says:

• uzela sam
• očistila sam
• oprala sam
• obrisala sam

A man would say:

• uzeo sam
• očistio sam
• oprao sam
• obrisao sam

Because Croatian usually drops subject pronouns when they are already clear from the verb form.

Here, sam already tells you it is I, and the participles show that the speaker is female. So ja is not necessary.

You could say Ja sam uzela metlu..., but that would usually add emphasis, contrast, or a more deliberate tone.

Because sam is a clitic, and Croatian clitics normally cannot stand at the very beginning of a clause.

So you can say:

• Uzela sam metlu
• Ja sam uzela metlu
• Metlu sam uzela

But not:

• Sam uzela metlu

A very common rule for learners is: clitics like sam tend to come in the second position of the clause.

Because this is a list of actions by the same subject in the same tense, so Croatian often states the auxiliary once and leaves it understood for the following verbs.

So this is natural:

• Uzela sam metlu, očistila kuhinju, oprala sudoper i obrisala pločice...

You could also repeat it:

• Uzela sam metlu, očistila sam kuhinju, oprala sam sudoper i obrisala sam pločice...

That is grammatical, but it sounds more repetitive.

Because metlu is the accusative singular form of metla.

Here, metlu is the direct object of uzela sam: the speaker took a broom.

For many feminine nouns ending in -a, the accusative singular ends in -u:

• metla → metlu
• kuhinja → kuhinju

Because the sentence says I took a broom, so broom is the direct object of uzeti, which requires the accusative: metlu.

Metlom is the instrumental form and would mean with a broom.

Compare:

• Uzela sam metlu. = I took a broom.
• Očistila sam kuhinju metlom. = I cleaned the kitchen with a broom.

So metlu and metlom are both correct forms, but they mean different things in different sentence roles.

They are both direct objects, so they are both in the accusative, but different noun types behave differently.

• kuhinja is a feminine noun in -a, so its accusative singular changes:
  kuhinja → kuhinju

• sudoper is a masculine inanimate noun, and for masculine inanimate nouns, the accusative is usually the same as the nominative:
  sudoper → sudoper

So the case is the same, but the form depends on the noun class.

Here pločice is the direct object of obrisala, so it is in the accusative plural.

The singular dictionary form is pločica. In the plural:

• nominative plural: pločice
• accusative plural: pločice

So yes, the form looks the same here. That is normal.

Pokraj means beside, next to, or by.

It requires the genitive case.

The noun vrata is a special noun: it is usually treated as plural in form, even when it means door in English. Its genitive plural is also vrata, so the form does not visibly change here.

So:

• pokraj vrata = beside / next to the door

This is one of those Croatian forms that looks simple on the surface but is actually grammatically special.

Yes. These are perfective verbs:

• uzeti
• očistiti
• oprati
• obrisati

Perfective verbs present the actions as completed whole actions. That fits the sentence very well, because it sounds like the speaker is listing finished tasks.

So the feeling is:

• she took the broom,
• cleaned the kitchen,
• washed the sink,
• wiped the tiles,

and those actions are all presented as completed.

You could, but the meaning would change.

Imperfective counterparts would be things like:

• uzimati
• čistiti
• prati
• brisati

These usually suggest an ongoing action, repeated action, habitual action, or background description rather than a neat list of completed tasks.

So for a finished sequence of chores, the perfective forms are the natural choice.

Because očistiti is a broad verb meaning to clean or to clean up thoroughly.

If you wanted to say specifically swept, you could use pomesti:

• Pomela sam kuhinju. = I swept the kitchen.

But in this sentence, the speaker is describing several cleaning actions in one sequence, so očistila kuhinju works well as a general cleaning action.

Yes, that is the most natural reading.

A list like this in Croatian normally sounds like a sequence of completed actions, told in the order they happened:

1. took the broom
2. cleaned the kitchen
3. washed the sink
4. wiped the tiles by the door

It is not a strict logical rule, but that is definitely the normal interpretation.

Yes, Croatian word order is flexible, but not completely free.

For example, you can move parts around for emphasis:

• Metlu sam uzela.
• Kuhinju sam očistila.

That changes the focus a bit. However, the clitic sam still has to follow the first element of the clause, so you still cannot start with sam by itself.

So the sentence can be rearranged, but the clitic-placement rule still matters.