בהתחלה לא הבנתי את המסר, אבל אחר כך הכול היה ברור יותר.

The ב־ is the preposition in / at attached directly to the noun התחלה (beginning).

So:

• התחלה = beginning
• בהתחלה = at the beginning / in the beginning / at first

This is very common in Hebrew: prepositions often attach as prefixes.

Examples:

• בבית = in the house
• בהתחלה = at the beginning

Because the word התחלה already has ה־ (the), the combination ב + ה becomes בה.

In Hebrew, negation in the past tense is usually very simple:

• לא = not
• past-tense verb = the action

So:

• הבנתי = I understood
• לא הבנתי = I did not understand

Hebrew does not use an extra helping verb like English did here.
You just put לא before the past-tense verb.

הבנתי is the past tense, first person singular form of the verb להבין (to understand).

So:

• להבין = to understand
• הבנתי = I understood

The ending ־תי is a very common marker for I in the past tense.

Other examples:

• כתבתי = I wrote
• למדתי = I studied / learned
• אמרתי = I said

So once you recognize ־תי, you can often identify I did... in the past.

את marks a definite direct object.

In this sentence:

• הבנתי את המסר = I understood the message

Here, המסר means the message, and it is the direct object of the verb understood.
Because it is definite (the message, not just a message), Hebrew uses את.

Compare:

• הבנתי מסר = I understood a message / message (less natural in many contexts)
• הבנתי את המסר = I understood the message

So את does not mean a separate English word here; it is a grammar marker.

מסר means message.
With ה־, it becomes המסר = the message.

So:

• מסר = message
• המסר = the message

The prefix ה־ is the Hebrew definite article, equivalent to English the.

They do two different jobs:

• אבל = but
• אחר כך = afterward / later / after that

So the structure is:

• אבל introduces contrast: but
• אחר כך adds the time idea: later

In other words:

• בהתחלה לא הבנתי את המסר = At first I didn’t understand the message
• אבל אחר כך = but afterward / but later
• הכול היה ברור יותר = everything was clearer

הכול means everything / all of it.

This word often appears as:

• הכול
• הכל

Both spellings are common; הכול reflects pronunciation more clearly for many learners.

Even though it begins with ה־, you should usually learn הכול as a complete word meaning everything.

Examples:

• הכול טוב = Everything is fine
• אני מבין הכול = I understand everything

Because הכול is treated as a singular idea in Hebrew.

So Hebrew says:

• הכול היה ברור יותר = everything was clearer

Even though everything may refer to many things conceptually, grammatically it often behaves like a singular noun. That is why the verb is היה (was, masculine singular), not היו (were).

This is similar to how English often uses singular forms with words like everything:

• Everything was clear not
• Everything were clear

Because ברור agrees with הכול, which is treated here as masculine singular.

So:

• ברור = clear, masculine singular
• ברורה = clear, feminine singular

Since הכול takes masculine singular agreement in this sentence, Hebrew uses:

• הכול היה ברור יותר

not

• הכול היה ברורה יותר

יותר means more.

So:

• ברור = clear
• ברור יותר = clearer / more clear

Hebrew often forms the comparative with:

• adjective + יותר

Examples:

• גדול יותר = bigger
• מהיר יותר = faster
• ברור יותר = clearer

So Hebrew does not usually need a special -er ending like English. It often just adds יותר.

Because the Hebrew structure is describing the state of everything, not the manner of an action.

• הכול היה ברור יותר literally means everything was more clear / clearer

This is an adjective phrase, not an adverb.

English also often says:

• Everything was clearer rather than
• Everything was understood more clearly

So the Hebrew sentence is using a very natural descriptive structure.

Hebrew often does not use extra dummy pronouns the way English sometimes does.

In English, you might say:

• it was clearer or
• everything was clearer

In Hebrew, the subject is already there:

• הכול = everything

So Hebrew simply says:

• הכול היה ברור יותר

No extra it is needed.

Yes, Hebrew word order is somewhat flexible.

The sentence given is:

• בהתחלה לא הבנתי את המסר

This puts emphasis on the time frame first: At first...

You could also hear:

• לא הבנתי את המסר בהתחלה

That is also natural, but it sounds slightly less fronted/emphatic.
Starting with בהתחלה helps set the scene immediately.

So both are possible, but the original sentence is very natural and common.

A simple pronunciation guide is:

ba-hat-kha-LA lo he-VAN-ti et ha-ME-ser, a-VAL a-KHAR kakh ha-KOL ha-YA ba-RUR yo-TER

A few notes:

• ח in בהתחלה and אחר is a throaty sound not found in standard English
• stress is often near the end of the word:
  • בהתחלה
  • הבנתי
  • אחר כך
  • ברור

If a learner cannot produce ח yet, an approximate h/kh sound is a common starting point.

It is normal, natural, everyday Hebrew.

Nothing in it sounds overly literary or unusually formal.
It would fit well in spoken or written modern Hebrew.

A native speaker might easily say this in conversation when describing confusion and later understanding:

• בהתחלה לא הבנתי את המסר, אבל אחר כך הכול היה ברור יותר.

So it is a very useful pattern to learn.