ניסיתי לאתר את ההודעה באפליקציה, אבל בסוף מצאתי אותה רק אחרי שקראתי שוב את כל ההודעות.

ניסיתי means I tried.

It comes from the verb לנסות = to try.
The ending ־תי is the common past-tense ending for I in Hebrew.

So:

• ניסיתי = I tried
• מצאתי = I found
• קראתי = I read

A useful pattern here is:

• verb stem + תי = I in the past

After ניסיתי = I tried, Hebrew usually uses an infinitive, just like English often uses to + verb.

So:

• ניסיתי לאתר = I tried to locate

Here, לאתר is the infinitive to locate / to track down.

This is a very common structure:

• ניסיתי להבין = I tried to understand
• ניסיתי למצוא = I tried to find
• ניסיתי להתקשר = I tried to call

They are related, but not identical.

• לאתר = to locate, to track down, to identify where something is
• למצוא = to find

So the sentence suggests a slight process:

• first, the speaker tried to locate the message
• in the end, they actually found it

Using both verbs sounds natural because לאתר emphasizes searching, while למצוא emphasizes the successful result.

את is the Hebrew direct object marker. It appears before a definite direct object.

So:

• את ההודעה = the message as a direct object
• את כל ההודעות = all the messages as a direct object

It does not mean with here. It is just a grammatical marker.

A key point: את is usually used before something definite, such as:

• ההודעה = the message
• הספר = the book
• כל ההודעות = all the messages

Examples:

• קראתי את הספר = I read the book
• מצאתי את המפתח = I found the key

Because אותה means her / it as a direct object, and it refers back to ההודעה.

Since הודעה is a feminine noun, the pronoun must also be feminine:

• הודעה = feminine singular
• אותה = it / her for a feminine singular object

So:

• מצאתי אותה = I found it

If the noun were masculine, Hebrew would use אותו instead.

Also, you do not add a separate את before אותה, because אותה is already the object form.

In unpointed Hebrew spelling, באפליקציה can represent either:

• בְאפליקציה = in an app
• בָאפליקציה = in the app

They are written the same way without vowel marks.

So only context tells you which one is meant. In this sentence, the meaning is probably in the app.

This happens a lot in Hebrew with the prepositions ב, ל, and כ when they combine with ה.

אבל means but.
בסוף here means in the end / eventually.

So:

• אבל בסוף = but in the end

A useful note: בסוף can sometimes also mean at the end, depending on context.
In this sentence, it clearly means the result after some effort, so in the end or eventually is the best reading.

Here, אחרי ש־ means after followed by a clause.

So:

• אחרי שקראתי = after I read
• more naturally in English here: after I had read / after I reread

The ש־ links אחרי to the following verb clause.

Compare:

• אחרי הארוחה = after the meal
• אחרי שקראתי = after I read

So if אחרי is followed by a full action clause, Hebrew often uses ש.

שוב means again.

So:

• קראתי שוב = I read again / I reread

Hebrew often places שוב after the verb, although word order can sometimes vary.

In this sentence:

• אחרי שקראתי שוב את כל ההודעות = after I read all the messages again

So the idea is not that the speaker read just one message again, but that they went through all the messages again.

כל ההודעות means all the messages.

When כל means all referring to a definite set, it is usually followed by a definite noun:

• כל ההודעות = all the messages
• כל הספרים = all the books
• כל הילדים = all the children

By contrast, כל can also mean every, usually with a singular noun:

• כל הודעה = every message
• כל ילד = every child

So:

• כל הודעה = every message
• כל ההודעות = all the messages

That is why את כל ההודעות fits this sentence.

Because one is singular and one is plural:

• הודעה = message
• הודעות = messages

Hebrew is talking first about one specific message:

• את ההודעה = the message

Then later about the larger set the speaker had to go through:

• את כל ההודעות = all the messages

Also notice the feminine plural ending ־ות in הודעות.
That matches the singular feminine noun הודעה.

It is actually quite close to English in structure:

• ניסיתי לאתר... = I tried to locate...
• אבל בסוף מצאתי אותה... = but in the end I found it...
• רק אחרי שקראתי שוב... = only after I read again...

What feels most Hebrew-specific here is:

• the use of את
• the object pronoun אותה
• the construction אחרי ש־
• the compact use of prepositions attached to words, like באפליקציה

So the overall sentence structure is fairly learner-friendly, even though some grammar details are very Hebrew.