U postele je malý stůl.

U is a preposition that usually means by, at, or near.
In U postele je malý stůl, it means something like by the bed or next to the bed.

So the sentence literally starts with a location:

• u postele = by the bed

Because the preposition u requires the genitive case.

The basic dictionary form is:

• postel = bed

But after u, it changes to:

• u postele = by the bed

This is a very common pattern in Czech:

• u domu = by the house
• u školy = by the school
• u postele = by the bed

It is the genitive singular of postel.

Here is the idea:

• nominative: postel = bed
• genitive: postele = of the bed / by the bed after u

So in this sentence, postele is not plural. It is still singular.

Je is the 3rd person singular form of být (to be), so it means is.

The sentence structure is basically:

• U postele = by the bed
• je = is
• malý stůl = a small table

So literally:

• By the bed is a small table

Natural English would usually be:

• There is a small table by the bed.

Because adjectives in Czech must agree with the noun they describe in:

• gender
• number
• case

The noun here is stůl (table), which is:

• masculine
• singular
• nominative

So the adjective must match:

• malý stůl = small table

For comparison:

• malá postel = small bed
• malé okno = small window
• malý stůl = small table

You usually learn the gender together with the noun.

Here:

• stůl is a masculine inanimate noun

That matters because it affects adjective endings:

• malý stůl
• not malá stůl
• not malé stůl

In the nominative singular:

• masculine inanimate: malý
• feminine: malá
• neuter: malé

Czech does not have articles like English a, an, and the.

So malý stůl can mean:

• a small table
• the small table

Which one is meant depends on the context.

In this sentence, English would most naturally say:

• There is a small table by the bed.

Czech word order is fairly flexible, but different orders change the focus or emphasis.

The given sentence:

• U postele je malý stůl.

This is a natural way to present a location first, then say what is there.

You could also say:

• Malý stůl je u postele. = The small table is by the bed.

The meaning is very similar, but the emphasis is different:

• U postele je malý stůl. → focuses more on what is by the bed
• Malý stůl je u postele. → focuses more on where the small table is

Not exactly.

• u = by, at, near
• vedle = next to, beside

So u postele can be a little broader: it means the table is somewhere by the bed.
Vedle postele is more specifically next to the bed.

In many everyday situations, both can work, but vedle is more exact.

Because stůl is the subject of the sentence, so it is in the nominative case:

• malý stůl = a small table

But postele comes after the preposition u, and u requires the genitive case:

• u postele = by the bed

So the two nouns have different roles:

• stůl = the thing that is
• postele = the place near which it is

A very literal translation would be:

• By the bed is a small table.

That is grammatical in English, but less natural in everyday speech.
More natural English is:

• There is a small table by the bed.
• A small table is by the bed.

So Czech and English organize this kind of sentence a bit differently.

Stůl is pronounced roughly like stool, but not exactly like the English word.

A few notes:

• ů is pronounced like a long oo
• the final l is a clear l
• the word is one syllable

So:

• stůl ≈ stoo-l

And the whole sentence is roughly:

• oo PO-steh-leh yeh MAH-lee stoohl

That is only an approximation, but it can help at the start.