W szafie przy łóżku trzymam ręczniki i pościel.

Because w means in here, and after w Polish uses the locative case when talking about location.

So:

• szafa = base form, wardrobe / closet / cabinet
• w szafie = in the wardrobe

This is one of the first big differences from English: Polish changes the noun ending depending on its role in the sentence.

Przy means by, next to, or near. It tells you that the wardrobe is located close to the bed.

Like w, the preposition przy also requires a specific case: the locative.

So:

• łóżko = bed
• przy łóżku = by / next to the bed

Because it is in the locative singular after przy.

The dictionary form is łóżko, but after przy it becomes łóżku.

This is just part of the noun’s declension pattern. In other words, you are not supposed to invent the ending from English logic; you learn that certain prepositions require certain cases, and then nouns change accordingly.

Not literally. Trzymać can mean to hold, but in many everyday sentences it also means to keep or to store.

So here trzymam ręczniki i pościel means:

• I keep towels and bedding
• I store towels and bedding

It does not sound like you are standing there physically holding them in your hands.

Because Polish usually leaves out subject pronouns when they are already clear from the verb ending.

Trzymam already means I keep / I am keeping because the ending -am shows first person singular.

So:

• trzymam = I keep
• ja trzymam = I keep, but with extra emphasis, contrast, or clarity

Polish does this a lot, so missing subject pronouns are completely normal.

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

But the forms look a little deceptive:

• ręczniki is accusative plural, but for masculine inanimate nouns, the accusative plural looks the same as the nominative plural.
• pościel is accusative singular, but its accusative singular looks the same as its nominative singular.

So even though the forms do not visibly change here, the grammatical case is still accusative.

In Polish, pościel is usually a singular collective / mass noun. It means bedding or bed linen as a category.

So Polish treats it more like English bedding than English sheets.

That is why the sentence uses:

• ręczniki = plural, countable
• pościel = singular, collective

If you want to name individual items, you would use different words, such as prześcieradło for sheet.

Most naturally, it describes the wardrobe.

So the most natural grouping is:

• w szafie przy łóżku = in the wardrobe by the bed

Because przy łóżku comes right after szafie, a learner should usually understand it as modifying szafie.

Yes. Polish word order is much more flexible than English word order.

For example, this is also natural:

• Trzymam ręczniki i pościel w szafie przy łóżku.

The difference is mostly about focus and emphasis:

• W szafie przy łóżku trzymam... puts the location first, as the topic.
• Trzymam... w szafie przy łóżku starts with the action.

Because Polish uses case endings, the meaning usually stays clear even when the order changes.

Szafa is a broad word. Depending on context, it can mean:

• wardrobe
• closet
• large cabinet
• cupboard

In this sentence, it is probably best understood as the wardrobe / closet by the bed.

So if you saw a translation with either wardrobe or closet, that would not be surprising.

Trzymam is:

• present tense
• first person singular
• from the imperfective verb trzymać

The imperfective is used because the sentence describes a normal, ongoing situation: where I keep these things.

So in English, depending on context, it could correspond to:

• I keep
• I am keeping

But here I keep is the most natural translation.

A rough English-friendly guide is:

• ł sounds like English w
• ó sounds like u in too
• ż sounds like the s in measure
• ku sounds like koo

So łóżku is approximately WOOZH-koo.

That is only an approximation, but it helps beginners. The full sentence also contains several sounds English speakers often need practice with, especially ł, ż, and the soft consonants in pościel.