Ara trobo la clau sota la taula.

Ara means now. It places the action in the present moment.

In this sentence, Ara trobo la clau sota la taula, it tells you that the finding is happening now.

Catalan often puts ara at the beginning, but it can move:

• Ara trobo la clau sota la taula.
• Trobo ara la clau sota la taula.
  The first one is the most natural and neutral.

Catalan usually leaves out subject pronouns when they are not needed, because the verb ending already shows who the subject is.

Here, trobo means I find, so jo is understood automatically.

You could say:

• Jo trobo la clau sota la taula.

But that would usually add emphasis, contrast, or clarity:

• Jo trobo la clau, però tu no.
  I find the key, but you don’t.

Trobo comes from the verb trobar, meaning to find.

Here it is:

• first person singular
• present tense

So:

• trobo = I find

A few present-tense forms of trobar are:

• trobo = I find
• trobes = you find
• troba = he/she finds
• trobem = we find
• trobeu = you all find
• troben = they find

Catalan often uses the simple present where English might use either the simple present or the present continuous.

So trobo can cover contexts where English would say:

• I find
• I’m finding

Catalan does have ways to express an ongoing action, but the simple present is very common and natural.

So in a sentence with ara, trobo can sound perfectly normal for an action happening right now.

Yes. Trobar has a few common meanings.

Most importantly:

• trobar = to find
• trobar que... = to think that... / to find that...

For example:

• Trobo la clau. = I find the key.
• Trobo que és difícil. = I think it’s difficult.

In your sentence, because la clau is a direct object, the meaning is clearly find, not think.

Because both nouns are feminine singular:

• la clau = the key
• la taula = the table

In Catalan, nouns have grammatical gender, and the article must match:

• el = masculine singular
• la = feminine singular
• els = masculine plural
• les = feminine plural

So:

• el llibre = the book
• la clau = the key

Because grammatical gender in Catalan is not determined only by the ending.

It is true that many feminine nouns end in -a, but not all of them do.
Clau is simply a feminine noun, so it takes la:

• la clau

This is something learners often need to memorize noun by noun.

Other feminine nouns that do not end in -a also exist, so the article is often your best clue.

Sota means under or beneath.

So:

• sota la taula = under the table

It introduces a location. In this sentence, it tells you where the key is found.

You may also see related expressions in Catalan, but sota la taula is a very standard and natural way to say under the table.

No, Catalan word order is fairly flexible, though some orders are more neutral than others.

The given sentence is a normal, straightforward order:

• Ara = time
• trobo = verb
• la clau = object
• sota la taula = place

You can sometimes move parts around for emphasis:

• Trobo la clau sota la taula ara.
• La clau la trobo sota la taula.

But the original version is the clearest neutral pattern for a learner.

In a Central Catalan pronunciation, roughly:

AH-ruh TROH-boh luh KLOW SOH-tuh luh TOW-luh

A few useful points:

• trobo: the o in the stressed syllable is open in many accents
• clau: au sounds a bit like ow in cow
• taula: also contains au, so again something like TOW-luh
• the r in ara is light, not like a strong English r

An approximate IPA version is:

/ˈaɾə ˈtɾɔβu lə ˈklaw ˈsotə lə ˈtawlə/

Yes, that is grammatically possible, but it is usually not the most neutral choice.

Adding jo gives extra emphasis:

• Ara jo trobo la clau sota la taula
  suggests something like I’m the one who finds the key now or contrasts with someone else.

In ordinary speech, Catalan usually prefers:

• Ara trobo la clau sota la taula.

Primarily, it is about the action of finding the key.
The phrase sota la taula tells you the location connected with that action.

So the structure is:

• trobo = I find
• la clau = the key
• sota la taula = under the table

In natural interpretation, it usually means that the key is found under the table.