Encontramos la bomba bajo el puente.

Encontramos is the nosotros form of encontrar and it can mean either:

• we find (present)
• we found (preterite / simple past)

That happens because the nosotros form looks the same in both tenses for many -ar verbs.

So this sentence by itself is ambiguous unless the context makes it clear. For example:

• Cada vez que buscamos bien, encontramos la bomba bajo el puente. = we find
• Ayer encontramos la bomba bajo el puente. = we found

In real life, the surrounding context usually tells you which meaning is intended.

La bomba uses the definite article, so it means the bomb rather than a bomb.

Spanish uses definite and indefinite articles much like English:

• la bomba = the bomb
• una bomba = a bomb

Using la suggests the speaker is talking about a specific bomb, or one that is already known in the conversation.

Also, bomba is a feminine singular noun, so it takes la.

The personal a is usually used before a specific human person (and sometimes pets or personified beings) when that noun is a direct object.

Examples:

• Vemos a María.
• Encontré a mi hermano.

But la bomba is an object, not a person, so you do not use the personal a:

• Encontramos la bomba ✔
• Encontramos a la bomba ✘

Yes. Both are possible, and both mean under the bridge.

• bajo el puente
• debajo del puente

A useful difference:

• bajo can work as a preposition by itself: bajo el puente
• debajo usually goes with de: debajo del puente

In many everyday contexts, debajo de sounds a little more common and natural in speech, but bajo is completely correct and common too.

So these are both good Spanish:

• Encontramos la bomba bajo el puente.
• Encontramos la bomba debajo del puente.

Because puente is a masculine noun in Spanish.

So:

• el puente = the bridge
• un puente = a bridge

There is no reliable rule that tells you all nouns ending in -e are masculine or feminine, so this is something you usually learn with the article:

• el puente
• la fuente
• el coche
• la noche

Learning the article together with the noun is the best habit.

In Spanish, de + el normally contracts to del.

So:

• de el puente becomes del puente

That is why you say:

• debajo del puente not
• debajo de el puente

This contraction also happens with a + el = al:

• Voy al puente.

But it does not happen with la:

• debajo de la mesa ✔

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

The most neutral order here is:

• Encontramos la bomba bajo el puente.

But you could also say:

• Bajo el puente encontramos la bomba.
• La bomba la encontramos bajo el puente. (more emphasis on la bomba)

The basic meaning stays the same, but the emphasis changes. Putting bajo el puente first can highlight the location. Putting la bomba first can highlight what was found.

Not always. Bomba can have several meanings depending on context.

Common ones include:

• bomb
• pump (for example, a water pump)
• in some contexts, a figurative shock or big news

So la bomba can be ambiguous in isolation. Context tells you what it means.

In your sentence, if the intended meaning has already been given, then that is the one the learner should follow.

A simple pronunciation guide:

• encontramos ≈ en-kon-TRAH-mos
• la bomba ≈ la BOM-ba
• bajo ≈ BA-ho
• el puente ≈ el PWEN-te

A few useful notes for Spain Spanish:

• j in bajo is a throaty sound, like a strong h
• ue in puente forms one syllable: pwen
• the stress is on -tra- in encontramos and on puen- in puente

Usually, no. For physical location like this, you normally use:

• bajo
• debajo de

So:

• bajo el puente
• debajo del puente

Abajo usually means down or downstairs/below, and it is not the normal choice here for under in the sense of directly beneath something.

So a learner should prefer:

• bajo el puente
• debajo del puente

not:

• abajo del puente for this meaning.