Saya membuat kelompok belajar kecil dengan teman sekelas supaya kami saling membantu.

Supaya introduces a purpose or goal, very much like “so that” / “in order that” in English.

• Saya membuat kelompok belajar kecil ... supaya kami saling membantu.
  → I made a small study group *so that we can help each other.*

It shows why the speaker created the study group.
You can think of it as: supaya = for the purpose that / so that.

Saling means “each other” / “one another” and it marks a reciprocal action.

• membantu = to help
• saling membantu = to help each other / to help one another

So the phrase supaya kami saling membantu emphasizes that help goes both ways, not just one person helping the others. You must use a verb after saling:

• saling mengenal = to know each other
• saling menyukai = to like each other
• saling menghormati = to respect each other

In Indonesian, the typical order is:

[noun] + (modifier noun) + adjective

Here:

• kelompok = group (main noun)
• belajar = study, studying (acts like a modifier: study group)
• kecil = small (adjective)

So:

• kelompok belajar = study group
• kelompok belajar kecil = a small study group

Adjectives like kecil, besar, baru, lama, etc., almost always come after the noun phrase they describe.

They refer to different “we” concepts and also to I vs we:

• saya = I (formal / neutral)
• kami = we (excluding the listener)

So the structure is:

• Saya membuat... = I made/created...
• supaya kami saling membantu. = so that we (I + my classmates, but not including the listener) help each other.

If the speaker wanted to include the listener in the group, they would say kita instead of kami:

• supaya kita saling membantu = so that we (including you) help each other.

Teman sekelas is a fixed, common expression meaning “classmate”.

• teman = friend
• sekelas = in the same class

So teman sekelas = friends who are in the same class as me → classmates.

You could say teman di kelas, but it’s less specific and more like “friends in (the) class,” not the standard single word concept “classmates.” Teman sekelas is the natural choice here.

Indonesian usually doesn’t mark plural with an -s like English. The form teman sekelas can be:

• one classmate
• several classmates

The number is understood from context.

In this sentence:

• Saya membuat kelompok belajar kecil dengan teman sekelas...

A study group naturally involves more than one person, so teman sekelas is understood as (some) classmates.

If you wanted to be extra clear that it’s plural, you could say:

• dengan beberapa teman sekelas = with several classmates
• dengan teman-teman sekelas = with my classmates (plural emphasis)

Membuat literally means “to make” and is very common and neutral. In this context, it means “to create / to form” a group.

You can use other verbs, but they change the nuance a bit:

• membentuk kelompok belajar kecil
  → to form/organize a small study group
• mendirikan kelompok belajar kecil
  → to establish a small study group (sounds more formal, like founding an organization)

For everyday, casual description of forming a study group with classmates, membuat is perfectly natural and common.

Yes, you can drop saya in conversation if the subject is clear from context:

• (Saya) membuat kelompok belajar kecil dengan teman sekelas supaya kami saling membantu.

However:

• With no subject, it might also sound like a general instruction:
  “(You should) make a small study group with classmates so that you help each other.”

Including saya makes it clear that this is something I did, not advice or an instruction.

Dengan is a preposition that usually means:

• with (companionship)
• using / by means of (instrument)
• in a ... way (manner)

Here it means “with” in the sense of together with someone:

• dengan teman sekelas = with (my) classmates

So the sentence part means:

• Saya membuat kelompok belajar kecil dengan teman sekelas
  → I made a small study group with classmates (i.e., together with them / consisting of them).

Indonesian often uses noun + verb as a compact noun phrase:

• kelompok belajar
  = study group (group for studying)

You could say:

• kelompok untuk belajar = a group to study / for studying

But kelompok belajar is:

• shorter
• more natural
• commonly used as the standard term “study group.”

So both are understandable, but kelompok belajar is the typical, idiomatic expression.

Grammatically, belajar is a verb (“to study”), but in combinations like kelompok belajar, it functions like a modifier, similar to how English uses a verb or gerund before a noun:

• study group → group (for) study
• kelompok belajar → group (for) study

Indonesian is very flexible this way: a verb can modify a noun directly without changing form, especially in set expressions like this.

Yes, with some nuance differences:

• supaya and agar are very close:
  Saya membuat kelompok belajar kecil ... agar/supaya kami saling membantu.
  Both mean “so that / in order that” and are mostly interchangeable.
  Agar can sound slightly more formal or written, but it’s a small difference.

• untuk is usually followed by a verb in root form or a noun, not a full clause with a subject:

  • Natural:
    
    • ... untuk saling membantu. = to help each other
  • Less natural:
    
    • ✗ ... untuk kami saling membantu. (sounds off)

So:

• supaya kami saling membantu
• agar kami saling membantu
• untuk saling membantu

All work, but with untuk, you drop “kami” and just use the verb phrase. The meaning is still “for the purpose of helping each other.”