בסוף השבוע קראתי את כל הספר.

Literally, בסוף השבוע breaks down as:

• ב־ = in / at / on
• סוף = end
• השבוע = the week

So the literal sense is at the end of the week. In modern Hebrew, though, סוף השבוע is also the normal way to say the weekend, so בסוף השבוע often means on the weekend or over the weekend.

This is because סוף השבוע is a construct chain (called סמיכות in Hebrew).

In this structure:

• the first noun is סוף = end of
• the second noun is השבוע = the week

Together: סוף השבוע = the end of the week / the weekend

In Hebrew construct chains, the definiteness is usually shown on the second noun, not the first. So you say:

• סוף השבוע = the weekend
  not
• הסוף השבוע

Hebrew often leaves out the subject pronoun when the verb already shows who the subject is.

Here, קראתי already means I read because the ending ־תי marks first person singular past.

So:

• קראתי = I read / I read
• אני קראתי = I read / I was the one who read

Adding אני is possible, but it usually adds emphasis or contrast.

The ending ־תי is the standard past-tense ending for I in many Hebrew verbs.

So:

• קרא = he read
• קראתי = I read

This ending works for both male and female speakers in the past tense first person singular. So a man and a woman would both say קראתי.

את is the marker of a definite direct object.

It does not have a separate English translation here. Its job is grammatical: it tells you that the next noun phrase is the direct object of the verb, and that it is definite.

So:

• קראתי ספר = I read a book
• קראתי את הספר = I read the book

In your sentence:

• את כל הספר = the whole book

Since this object is definite, Hebrew uses את.

Because the noun inside the phrase is definite: הספר = the book.

So:

• כל ספר = every book / any book of the type book
• כל הספר = the whole book

That is why the sentence has:

• את כל הספר

and not just

• כל ספר

In Hebrew, כל + definite singular noun often means the whole / the entire.

So:

• כל הספר = the whole book
• כל היום = the whole day
• כל הלילה = the whole night

Be careful, because כל can mean different things depending on the noun phrase:

• כל ספר = every book
• כל הספר = the whole book

So the ה־ on הספר makes a big difference.

Yes. Both are possible:

• את כל הספר
• את הספר כולו

Both mean the whole book.

A small difference in feel:

• כל הספר is very common and neutral
• הספר כולו can sound a little more emphatic, sometimes a little more formal

So your sentence could also be:

• בסוף השבוע קראתי את הספר כולו.

Hebrew word order is fairly flexible. Putting בסוף השבוע first sets the time frame right away:

• בסוף השבוע קראתי את כל הספר. = Over the weekend, I read the whole book.

You could also say:

• קראתי את כל הספר בסוף השבוע.

That is also natural. The difference is mostly about emphasis and flow, not basic meaning.

Yes, in this sentence it normally sounds like a completed past action: I read the whole book.

Because the object is the whole book, the sentence strongly suggests completion. In other words, the idea is that by the end of that time period, the speaker had finished it.

So the sentence is naturally understood as:

• Over the weekend, I read the whole book.
• in other words, I finished reading it

It is the preposition ב־ attached directly to the noun סוף.

So:

• ב = in / at / on
• סוף = end
• בסוף = at the end / in the end

This is very common in Hebrew. Some short prepositions attach directly to the following word, especially:

• ב־ = in / at
• ל־ = to / for
• כ־ = as / like
• מ־ = from

So בסוף השבוע is a perfectly normal attached form.