La potoj staras en grupo.

In Esperanto, -j marks the plural.
So:

• poto = pot
• potoj = pots

That is why La potoj means the pots.

La is the definite article, meaning the.

So:

• la potoj = the pots

Esperanto has only one definite article, la. It does not change for singular/plural, gender, or case in this sentence.

Staras comes from stari, which means to stand or to be standing.

Esperanto often prefers a more specific verb when talking about position:

• stari = stand
• sidi = sit
• kuŝi = lie

So La potoj staras en grupo gives the idea that the pots are standing/positioned in a group, not just that they exist.

Using estas would be more general: The pots are in a group.
Using staras sounds more physical and visual.

Staras is present tense.

In Esperanto, verb endings are very regular:

• -as = present
• -is = past
• -os = future
• -us = conditional
• -u = command/jussive
• -i = infinitive

So:

• staras = stand / are standing

The -n ending usually marks the direct object, or sometimes motion toward something.

In this sentence:

• La potoj is the subject
• en grupo is a prepositional phrase

There is no direct object, so no accusative -n is needed.

Compare:

• La potoj staras en grupo. = The pots stand in a group.
• Mi vidas la potojn. = I see the pots.
  Here potojn gets -n because it is the direct object.

Literally, it means in a group.

• en = in
• grupo = group

So en grupo describes how the pots are arranged: they are in a group, grouped together.

Yes, grupe is possible in many contexts and means as a group or in a grouped way.

But there is a slight difference in feel:

• en grupo = in a group, as an arrangement or position
• grupe = grouped, collectively, in a grouped manner

For physical arrangement of objects, en grupo is very natural.

Because the pots form one group.

So:

• en grupo = in a group
• en grupoj = in groups

If there were several separate clusters of pots, then en grupoj might make sense.

Not completely. Esperanto word order is fairly flexible, though the normal order is subject–verb–other information:

• La potoj staras en grupo.

You could also move parts for emphasis, for example:

• En grupo staras la potoj.

But the original order is the most neutral and natural for learners.

Potoj is pronounced roughly PO-toy.

In Esperanto, j sounds like English y in yes. So:

• potoj ≈ po-toy

The letters are pronounced consistently, which is one of Esperanto’s easiest features.

Usually poto means a pot, especially a container such as a flowerpot, cooking pot, or similar vessel, depending on context.

As with many words, the exact English translation depends on the situation. But pot is the basic meaning, and here pots is the natural translation.