Najpierw kupujemy białą farbę i dwa pędzle.

Kupujemy means we buy or we are buying.

It comes from the verb kupować = to buy.
This form is:

• 1st person plural = we
• present tense
• imperfective aspect

So kupujemy can mean:

• we buy (general present)
• we are buying (current action)
• in instructions or narration, it can also sound like we buy / we’re going to buy as the next step

In a sentence like this, it often sounds like someone is describing steps in a process: First, we buy...

Najpierw means first or first of all.

It is used to show sequence, especially when describing steps:

• Najpierw... = First...
• then maybe potem... = then...
• then na końcu... = finally...

So the sentence sounds like part of a set of instructions or a plan.

Because farbę is in the accusative case, and the adjective has to match it.

The basic form is:

• biała farba = white paint (dictionary / nominative form)

But in this sentence, paint is the direct object of kupujemy (we buy what?) so Polish uses the accusative:

• farba → farbę
• biała → białą

So:

• biała farba = white paint
• kupujemy białą farbę = we buy white paint

This is a very common pattern in Polish: adjectives change together with the noun.

Because farba is a feminine noun, and feminine nouns often change in the accusative singular.

Here are the forms:

• farba = nominative singular
• farbę = accusative singular

Since kupować takes a direct object, we ask:

• Kupujemy co? = What are we buying?
• farbę

So farbę is required, not farba.

Because the adjective must agree with farbę in:

• gender: feminine
• number: singular
• case: accusative

The nominative feminine singular form is:

• biała

But the accusative feminine singular form is:

• białą

So:

• biała farba = white paint
• białą farbę = white paint as the object of the verb

This agreement is one of the most important features of Polish grammar.

Because pędzel is a masculine noun.

In Polish, 2 has different forms depending on gender:

• dwa for many masculine and neuter nouns
• dwie for feminine nouns

Examples:

• dwa pędzle = two brushes
• dwa okna = two windows
• dwie farby = two paints / two cans of paint

Since pędzel is masculine, the correct form is dwa.

Because the sentence refers to two brushes, so the noun must be plural.

The singular is:

• pędzel = brush

The plural used here is:

• pędzle = brushes

After dwa, Polish normally uses the plural noun form:

• dwa pędzle = two brushes

This is the standard pattern for many nouns after 2, 3, 4.

Because pędzle is a masculine inanimate plural noun, and for this type of noun, the accusative plural is usually the same as the nominative plural.

So:

• nominative plural: pędzle
• accusative plural: pędzle

That is why after kupujemy you still see dwa pędzle.

By contrast, feminine singular nouns often show a clearer accusative change:

• farba → farbę

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

So Polish simply says:

• kupujemy farbę

and the listener understands from context whether it means:

• we buy paint
• we buy the paint
• we buy some paint
• we buy a can of paint

The same is true for pędzle:

• dwa pędzle = two brushes / the two brushes, depending on context

Yes. Polish word order is more flexible than English, although some orders sound more natural in neutral speech.

The original sentence:

• Najpierw kupujemy białą farbę i dwa pędzle.

is a very natural neutral order.

You could also say:

• Białą farbę i dwa pędzle kupujemy najpierw.
• Najpierw białą farbę i dwa pędzle kupujemy.

But these alternatives may sound more marked, emphatic, or stylistically different.

For a learner, the original version is the best standard model.

Because it comes from the imperfective verb kupować, it does not strongly emphasize completion.

It focuses more on the action/process:

• kupujemy = we buy / are buying

If you wanted a perfective idea such as we will buy as a completed step, Polish might use a perfective verb like kupić, for example:

• Najpierw kupimy białą farbę i dwa pędzle. = First, we will buy white paint and two brushes.

So the sentence with kupujemy sounds more like describing a process, instructions, or a current plan in a natural, step-by-step way.

These two words can be tricky.

• białą is roughly pronounced BYA-woh or BYA-won depending on speed and accent
• farbę is roughly FAR-beh or FAR-bem in natural speech

A few notes:

• ą and ę are nasal vowels in Polish
• in real speech, their pronunciation often changes depending on the following sound
• before some consonants, they may sound less purely nasal than learners expect

Also:

• biał- sounds like byał-, not like English bee-a...
• pędzle begins with a nasal ę, and the cluster -dzl- can be difficult at first

A rough full pronunciation guide might be:

• Najpierw kupujemy białą farbę i dwa pędzle
• NAI-pyerv koo-poo-YE-my BYA-woh FAR-beh ee dva PEND-zle

That is only approximate, but it helps as a starting point.

Usually farba most commonly means paint in everyday contexts, especially with something like pędzle (brushes), which strongly suggests painting.

Depending on context, farba can also refer to coloring substances such as dye, for example:

• farba do włosów = hair dye
• farba drukarska = printing ink

But in this sentence, białą farbę i dwa pędzle, the natural meaning is definitely white paint and two brushes.