kapeeseoneun noteubuk daesin taebeulliseuro sueop jaryoreul bogon hae.

카페에서는 is made from:

• 카페 = cafe
• 에서 = at/in (location where an action happens)
• 는 = topic marker, often adding a sense of as for... or in the case of...

So 카페에서는 means something like:

• at a cafe
• when I'm at a cafe
• as for in cafes...

The 는 often adds a slight contrastive feeling. It can suggest:

• At cafes, I do it this way
  (maybe in other places, I do something different)

Without 는, 카페에서 would sound more neutral: just at a cafe.
With 는, the speaker is setting the cafe situation up as the topic or contrast.

대신 means instead of or in place of.

With nouns, Korean often uses:

• N 대신
• N 대신에

So:

• 노트북 대신 = instead of a laptop
• 노트북 대신에 = same meaning, just slightly fuller

You normally do not say 노트북을 대신 here, because 대신 is not working like a normal verb that takes 을/를 in this sentence. It is functioning more like a postposition/expression meaning in place of.

So the structure is:

• 노트북 대신 태블릿으로
  = using a tablet instead of a laptop

Here, -으로 marks the means/tool/method used to do something.

So:

• 태블릿으로 = with a tablet / using a tablet

In this sentence, the speaker is saying they look at the class materials using a tablet.

This is a very common use of -으로:

• 펜으로 써요 = I write with a pen
• 버스로 가요 = I go by bus
• 휴대폰으로 봐요 = I watch/look on a phone

So 태블릿으로 수업 자료를 보다 means:

• to look at the lesson materials on a tablet
• to use a tablet to view the lesson materials

Yes, 보다 basically means to see/look/watch, but in Korean it is used very broadly.

With things like documents, notes, or written content, 보다 often means:

• look at
• read
• check
• review

So:

• 수업 자료를 봐요 can mean
  I look at the lesson materials
  I read the class materials
  I check the lesson materials

It does not necessarily mean just physically seeing them with your eyes. It often includes the idea of viewing or going through the content.

Also, 자료 is often an uncountable or collective noun in Korean, so 수업 자료 can naturally mean:

• class materials
• lesson materials
• course materials

without needing a separate plural marker.

보곤 해 comes from 보고는 해, which is a shortened form of -고는 하다.

This grammar expresses a habitual or repeated action, often with a nuance like:

• I tend to...
• I often...
• I do ... sometimes/as a habit

So:

• 수업 자료를 보곤 해 =
  I often look at the lesson materials
  I tend to check the class materials
  I sometimes make a habit of looking at the materials

This is different from:

• 봐 / 봐요 = just look / watch / read in a simple present sense

Compare:

• 수업 자료를 봐요 = I look at the materials.
• 수업 자료를 보곤 해요 = I often/tend to look at the materials.

So -곤 하다 adds the idea of usual repeated behavior.

Because this is not the normal connective -고 meaning and.

It is the grammar pattern:

• -고는 하다 → often shortened to -곤 하다

So:

• 보다 + 고는 하다
• becomes 보고는 하다
• and commonly contracts to 보곤 하다

In casual speech:

• 보곤 해

This is a fixed grammatical pattern, so 보곤 해 should be understood as one unit meaning tend to look / often look.

If you said 보고 해, that would sound like:

• look at it and do (something)

which is a completely different structure.

해 is the casual, non-polite speech style.

So 보곤 해 is something you would say:

• to a friend
• to someone younger
• in casual writing
• when speaking informally

Polite versions would be:

• 카페에서는 노트북 대신 태블릿으로 수업 자료를 보곤 해요.
• or more formal/plain written style: 카페에서는 노트북 대신 태블릿으로 수업 자료를 보곤 한다.

So the meaning stays the same, but the level of politeness changes.

Yes, the subject is omitted, which is extremely common in Korean.

From the ending 해, the implied subject is usually:

• I
• or sometimes we, depending on context

So the full idea might be:

• 저는 카페에서는 노트북 대신 태블릿으로 수업 자료를 보곤 해요.

But Korean often leaves out subjects when they are obvious from context.

That is why a natural English translation has to add the subject:

• I often look at class materials on a tablet instead of a laptop at cafes.

Even though I is not actually spoken in the Korean sentence.

Yes, very often it does.

Because of the added 는, the sentence can imply something like:

• At cafes, I use a tablet instead of a laptop
• maybe but in other places I use a laptop
• or this is specifically what I do in cafes

The contrast does not have to be stated directly, but 는 often creates that feeling.

For example, this sentence could fit into a larger conversation like:

• 집에서는 노트북을 쓰고, 카페에서는 노트북 대신 태블릿으로 수업 자료를 보곤 해.
• At home I use a laptop, and at cafes I tend to look at lesson materials on a tablet instead.

So yes, 카페에서는 can feel slightly contrastive.

Yes, very naturally.

The sentence is structured like this:

• 노트북 대신 = instead of a laptop
• 태블릿으로 = using a tablet
• 수업 자료를 보곤 해 = I often look at the lesson materials

So the whole thing means:

• Instead of a laptop, I often use a tablet to look at lesson materials at cafes.

This combination is common because the speaker is expressing both:

1. the thing being replaced
2. the tool that is actually used

So it is perfectly natural to say:

• A 대신 B로 ... 하다
• do something with B instead of A

Usually 태블릿으로 is better here.

• 태블릿으로 보다 focuses on the device as the means/tool
• 태블릿에서 보다 focuses more on the device as the place/surface where something appears

Both can sometimes make sense, but they feel a little different.

For example:

• 휴대폰으로 영상을 봐요 = I watch videos on/with my phone
• 휴대폰에서 영상을 봐요 = I watch videos on the phone
  (more focus on where the content is being viewed)

In your sentence, 태블릿으로 sounds very natural because the speaker is contrasting devices:

• not with a laptop, but with a tablet

So -으로 is especially fitting.

A helpful breakdown is:

• 카페에서는 = at cafes / when at a cafe
• 노트북 대신 = instead of a laptop
• 태블릿으로 = using a tablet
• 수업 자료를 = lesson materials
• 보곤 해 = often/tend to look at

So the pattern is basically:

[Place/topic] + [A instead of] + [B as tool] + [object] + [habitual action]

In simpler form:

At cafes, instead of A, I often use B to look at C.

That makes the grammar much easier to understand piece by piece.