Гончарная мастерская уже открыта.

In Russian, the verb to be is usually omitted in the present tense.

So:

• Гончарная мастерская уже открыта. = The pottery workshop is already open.

Literally, Russian says something closer to:

• Pottery workshop already open.

This is completely normal in Russian. You would only use forms of быть in the past or future, or in certain special constructions.

Открыта is the short form of открытый and is commonly used after the subject to describe a state.

Compare:

• открытый / открытая / открытое = the full form, used before a noun
  
  • открытая дверь = an open door
• открыт / открыта / открыто / открыты = the short form, used as the predicate
  
  • дверь открыта = the door is open

Here, мастерская is feminine singular, so the short form must also be feminine singular:

• мастерская открыта

So this sentence means the workshop is in the state of being open.

Because it is an adjective agreeing with мастерская, which is:

• feminine
• singular
• nominative

Russian adjectives must agree with the noun they describe.

So:

• гончарный = masculine
• гончарная = feminine
• гончарное = neuter
• гончарные = plural

Since мастерская is feminine singular, you get:

• гончарная мастерская

Уже means already.

It often suggests one of these ideas:

• something has happened by now
• something happened earlier than expected
• there is a contrast with an earlier time

So:

• мастерская открыта = the workshop is open
• мастерская уже открыта = the workshop is already open

The second version adds the sense of by now / already.

It is in the nominative case.

Why? Because it is the subject of the sentence — the thing being described as open.

So:

• гончарная мастерская = nominative subject
• открыта = predicate describing its state

This is a very common Russian pattern:

• Магазин открыт. = The store is open.
• Дверь закрыта. = The door is closed.
• Школа уже открыта. = The school is already open.

Yes, мастерская is a noun here, meaning workshop or studio.

It does look adjective-like because it ends in -ая, but in modern Russian it is a normal feminine noun:

• мастерская = workshop / studio

So in this sentence:

• гончарная = adjective
• мастерская = noun

Together they mean pottery workshop or pottery studio.

Yes, but it means something slightly different.

• Гончарная мастерская уже открыта = The pottery workshop is already open
  → focuses on the current state
• Гончарная мастерская уже открылась = The pottery workshop has already opened
  → focuses on the event/change

So:

• открыта = state
• открылась = action/result of opening

In many situations both are possible, but they are not identical.

Yes. Russian word order is fairly flexible, but changing it changes the emphasis.

The most neutral version is:

• Гончарная мастерская уже открыта.

Other possible orders:

• Уже открыта гончарная мастерская.
  This puts more emphasis on already open.
• Гончарная мастерская открыта уже.
  This is possible, but sounds more marked or contrastive.

For learners, the original order is the safest and most natural neutral choice.

Russian has no articles.

So мастерская can mean:

• a workshop
• the workshop

Context tells you which one is meant.

In English, you have to choose. In a normal context, this sentence will often be translated as:

• The pottery workshop is already open.

But Russian itself does not explicitly mark a/the.

A useful stressed version is:

• гонча́рная мастерска́я уже́ откры́та

The main stress falls on:

• гонча́рная
• мастерска́я
• уже́
• откры́та

Getting the stress right is important in Russian, because it is not always predictable from spelling.