Monitor a klávesnice jsou na stole.

Because the subject is compound: monitor a klávesnice = the monitor and the keyboard. Two things together take a plural verb, so Czech uses jsou = are.

• monitor je na stole = the monitor is on the table
• klávesnice je na stole = the keyboard is on the table
• monitor a klávesnice jsou na stole = the monitor and the keyboard are on the table

It is the subject of the sentence, so it stays in the nominative case, which is the dictionary form.

Here, monitor is simply the monitor as the thing being talked about.

For the same reason: it is also part of the subject, so it is in the nominative.

A useful thing to know is that klávesnice can look the same in more than one grammatical form, but in this sentence it is nominative because it is one of the things that are on the table.

Because this sentence describes location, not movement.

With na:

• na + accusative often means movement onto something
  
  • Dám monitor na stůl. = I’ll put the monitor onto the table.
• na + locative means location on something
  
  • Monitor je na stole. = The monitor is on the table.

So in your sentence, the monitor and keyboard are already there, so Czech uses na stole.

It is the locative singular of stůl.

• nominative: stůl = table
• locative after na for location: na stole = on the table

This is a very common pattern in Czech: a preposition changes the case of the noun after it.

Yes. A is the normal Czech word for and.

So:

• monitor a klávesnice = the monitor and the keyboard

It joins the two nouns into one plural subject.

Because Czech does not use articles like English the and a/an.

So:

• monitor can mean a monitor or the monitor
• klávesnice can mean a keyboard or the keyboard
• stůl / stole can mean a table / the table

The exact meaning depends on context.

Yes. Czech word order is more flexible than English word order.

Your sentence:

• Monitor a klávesnice jsou na stole.

Another natural version:

• Na stole jsou monitor a klávesnice.

Both are correct. The difference is mainly in focus:

• Monitor a klávesnice jsou na stole. → talks first about the objects
• Na stole jsou monitor a klávesnice. → emphasizes the location first

In a normal full sentence, no. You should keep jsou.

Czech often omits the subject pronoun, but not the verb itself in a standard sentence like this.

So:

• correct: Monitor a klávesnice jsou na stole.
• not standard as a normal sentence: Monitor a klávesnice na stole.

You might see omission only in special styles such as notes, labels, or headlines.

Jsou is pronounced roughly like ysoh.

A few tips:

• the j sounds like English y
• ou sounds somewhat like oh in this word

So jsou does not sound like English j-sow.

Czech stress is usually on the first syllable, so the stress is on klá-:

• KLÁ-ves-ni-ce

Approximate pronunciation:

• klá like klaa
• ves like vess
• ni like nee
• ce like tseh

Also, á is a long vowel, so it is held a bit longer than a short a.

Here it is singular: keyboard.

The whole subject is plural because it has two singular nouns joined by and:

• monitor = one monitor
• klávesnice = one keyboard

Together:

• monitor a klávesnice = the monitor and the keyboard

That is why the verb is plural: jsou.