Мы обыскали комнату и нашли тайник.

Because the subject is мы = we, both verbs are in the past tense plural.

In Russian past tense:

• masculine singular often ends in -л
• feminine singular in -ла
• neuter singular in -ло
• plural in -ли

So:

• мы обыскали = we searched
• мы нашли = we found

The plural ending -ли matches мы.

Обыскали comes from обыскать, which means to search thoroughly, to search through, or even to conduct a search of a place.

That is stronger and more specific than искать, which usually means to look for something.

So:

• искали ключ = were looking for a key
• обыскали комнату = searched the room thoroughly

In this sentence, обыскали комнату suggests a complete search of the room, not just casually looking around.

Because комнату is the accusative case, used here for the direct object of the verb обыскали.

The base form is:

• комната = room

But after a transitive verb like обыскать (to search), the direct object goes into the accusative:

• обыскали комнату = searched the room

Since комната is a feminine noun ending in -а, its accusative singular changes to -у:

• комната → комнату

Because тайник is also a direct object, so it is in the accusative case. But тайник is a masculine inanimate noun, and for masculine inanimate nouns, the accusative singular is usually the same as the nominative.

So:

• nominative: тайник
• accusative: тайник

That is why нашли тайник keeps the same form.

Тайник means a hiding place, secret stash, cache, or secret compartment, depending on context.

It usually refers to a place where something is hidden, not just the hidden object itself.

So нашли тайник is more like:

• found a hiding place
• found a secret cache
• found a concealed compartment

The best English translation depends on the situation.

Both обыскали and нашли are perfective past forms. Perfective verbs usually present actions as completed whole events with a result.

Here that fits very well:

• first, we searched the room
• then, we found the hiding place

The sentence is about completed actions and their outcome.

Compare:

• Мы обыскивали комнату и находили тайник would sound odd in most contexts, because it focuses on process or repeated action, not a single completed result.
• Мы обыскали комнату и нашли тайник naturally tells a finished sequence.

Literally, и means and. But in this sentence, because both verbs are completed actions and appear in sequence, English often understands it as:

• We searched the room and found the hiding place or even
• We searched the room and then found the hiding place

So и itself does not literally mean then, but the sequence of events is very clear from the context.

Because и is connecting two verbs with the same subject:

• Мы обыскали
• (мы) нашли

This is a normal compound predicate structure, so no comma is needed.

A comma would usually appear only in more complex situations, not in a simple sentence like this one.

Yes. Russian word order is flexible, because case endings show grammatical roles.

The neutral order here is:

• Мы обыскали комнату и нашли тайник.

But you could change it for emphasis, for example:

• Комнату мы обыскали и нашли тайник.
• Тайник мы нашли, обыскав комнату.

These alternatives shift emphasis or style. The original sentence is the most straightforward and neutral.

The main stress is:

Мы обыскАли кОмнату и нашлИ тайнИк.

A rough pronunciation guide:

• Мы = my but with a Russian ы sound
• обыскАли = ah-bih-SKAH-lee
• кОмнату = KOM-nuh-too
• и = ee
• нашлИ = nahsh-LEE
• тайнИк = tie-NEEK

The most important thing for a learner is to remember the stress:

• обыскАли
• кОмнату
• нашлИ
• тайнИк

Russian has no articles like English a and the.

So:

• комнату can mean the room or a room
• тайник can mean the hiding place or a hiding place

Which one sounds best in English depends on context. In many contexts, Мы обыскали комнату и нашли тайник would naturally become We searched the room and found a hiding place / a secret compartment or ...found the hiding place, depending on what has already been mentioned.

Yes, that is the natural interpretation.

Мы обыскали комнату и нашли тайник strongly suggests that during the search of the room, the speakers discovered a hidden place there.

The sentence does not explicitly say в комнате (in the room), but the connection is understood from the context and the sequence of actions.