На столе лежат жёлтый маркер, оранжевая папка и фиолетовая тетрадь.

Because на столе answers the question where? and expresses location: on the table.

After на, Russian uses:

• accusative for motion toward something: на стол = onto the table
• prepositional for location: на столе = on the table

So here, the objects are already there, not moving there, so Russian uses the prepositional case:

• стол → на столе

Because the subject is a list of three things:

• жёлтый маркер
• оранжевая папка
• фиолетовая тетрадь

Together, they form a compound subject, so the verb is plural:

• лежит = lies / is lying for one thing
• лежат = lie / are lying for more than one thing

So лежат agrees with the whole group.

Russian often uses verbs like:

• лежать = to be lying
• стоять = to be standing
• висеть = to be hanging

English often just says there is / there are, but Russian prefers a more physical description of how something is positioned.

So:

• На столе лежат... literally means On the table lie...
• In natural English, you might translate it as There are ... on the table

Since a marker, folder, and notebook are thought of as resting flat on the table, лежать is the natural verb.

Because adjectives in Russian must agree with the noun they describe in gender, number, and case.

Here all three nouns are singular and nominative, but they have different genders:

• маркер — masculine → жёлтый маркер
• папка — feminine → оранжевая папка
• тетрадь — feminine → фиолетовая тетрадь

So the adjective endings change to match the noun.

Very roughly:

• masculine nominative singular: -ый / -ий / -ой
• feminine nominative singular: -ая / -яя

A common first clue is the noun ending.

• Nouns ending in a consonant are often masculine:
  маркер
• Nouns ending in -а / -я are often feminine:
  папка
• Nouns ending in -ь can be masculine or feminine, so you have to learn them individually:
  тетрадь is feminine

So:

• маркер → masculine
• папка → feminine
• тетрадь → feminine

Because each noun names one individual item:

• one marker
• one folder
• one notebook

Russian is listing separate singular objects, joined by and. The singular nouns are normal here. What becomes plural is the verb, because the whole subject is plural as a group.

Compare:

• На столе лежит жёлтый маркер. = One marker is lying on the table.
• На столе лежат жёлтый маркер, оранжевая папка и фиолетовая тетрадь. = A marker, a folder, and a notebook are lying on the table.

Russian word order is flexible, and the beginning of the sentence often gives the setting or topic first.

So На столе sets the scene:

• On the table, there are...

This is very natural in Russian.

Other word orders are possible, for example:

• Жёлтый маркер, оранжевая папка и фиолетовая тетрадь лежат на столе.

That version is also grammatical, but it feels a bit more like you are first naming the objects and then saying where they are. The original sentence is a very natural way to present location first.

Russian has no articles. There is no direct equivalent of a/an or the.

So:

• маркер can mean a marker or the marker
• папка can mean a folder or the folder
• тетрадь can mean a notebook or the notebook

Context tells you which meaning is intended. In this sentence, English would usually use a:

• On the table there are a yellow marker, an orange folder, and a purple notebook

Yes. The letter ё is pronounced yo and is always stressed.

So:

• жёлтый is pronounced roughly like ZHYOL-tyy

A useful thing to know: in many printed texts, Russian often writes е instead of ё, so you may sometimes see желтый, even though it is pronounced жёлтый.

For learners, it is helpful to remember that when ё is written, it clearly shows both the vowel sound and the stress.

Because Russian uses commas to separate items in a list, just like English:

• жёлтый маркер, оранжевая папка и фиолетовая тетрадь

This is the standard pattern:

• item 1, item 2 and item 3

So the comma separates the first two items, and и introduces the last one.

Usually, лежат is better and more natural here.

Russian can use есть to mean there is/there are, but in simple statements about where objects are, especially when their position is clear, Russian often prefers a positional verb like:

• лежать for things lying
• стоять for things standing
• висеть for things hanging

So:

• На столе есть маркер... is possible in some contexts, especially if you are emphasizing existence
• На столе лежит / лежат... is more natural when simply describing what is on the table

Because the adjectives describe each noun separately, and each noun has its own gender.

If you said жёлтые, that would be plural, but маркер is singular. Also, only the marker is yellow; the folder is orange and the notebook is purple.

So Russian keeps each noun phrase separate:

• жёлтый маркер
• оранжевая папка
• фиолетовая тетрадь

Each adjective matches its own noun.

They are in the nominative case, because they are the subject of the sentence.

The things doing the grammatical job of “lying on the table” are:

• жёлтый маркер
• оранжевая папка
• фиолетовая тетрадь

So both the nouns and the adjectives are nominative:

• жёлтый
  • маркер
• оранжевая
  • папка
• фиолетовая
  • тетрадь

Only столе changes case here, because it comes after на in a location expression.