Learn Hardcore Indonesian: Saya mengatur alarm untuk pukul tujuh.

menyetel/setel (to set/tune): Saya setel alarm jam tujuh.
memasang/pasang (to put on/activate): Saya pasang alarm jam tujuh.
mengaktifkan/aktifkan (to activate): Saya aktifkan alarm untuk pukul tujuh.

Your sentence is correct and clear; setel or pasang just sound a bit more colloquial/natural in daily speech.

Why is untuk used? Could I use pada or drop the preposition?

untuk = “for,” so …alarm untuk pukul tujuh = “the alarm for 7 o’clock” (the ring time).
pada = “at,” and would attach to the action time. Saya mengatur alarm pada pukul tujuh means “I set the alarm at 7,” not that it will ring at 7.
You can drop untuk: Saya (setel/atur) alarm pukul tujuh. This is very common and still means the alarm time is 7.

What’s the difference between pukul and jam?

Both mean “o’clock/time,” but:

pukul is a bit more formal/announcer style (you’ll hear it in schedules, announcements).
jam is the everyday word in conversation. All are acceptable: pukul tujuh, jam tujuh, pada pukul tujuh (formal).

How do I say 7 a.m. vs 7 p.m.?

Use time-of-day words or 24-hour time:

Morning: pukul/jam tujuh pagi (07.00)
Evening: pukul/jam tujuh malam (19.00) You’ll also see 24-hour clocks in writing: 07.00 vs 19.00.

What tense is this—past, present, or future?

Indonesian doesn’t mark tense on the verb. Context or time words tell you:

Past: Saya tadi/barusan mengatur alarm…
Progressive: Saya sedang mengatur alarm…
Future: Saya akan/nanti saya mengatur alarm… Your sentence can mean “I set / I’m setting / I’ll set,” depending on context.

Can I omit the subject Saya?

Yes, if context already makes the subject clear: Mengatur alarm untuk pukul tujuh. In isolation, that can feel like a note/reminder. To sound neutral and complete, keeping Saya is safest.

Is the word order fixed? Could I say Saya mengatur pukul tujuh alarm?

Keep the object near the verb, then the time phrase:

Natural: Saya mengatur alarm (untuk) pukul tujuh.
Unnatural: Saya mengatur pukul tujuh alarm. You can front the time for emphasis: Untuk pukul tujuh, saya mengatur alarm.

Does pukul also mean “to hit”? Is that confusing?

Yes, pukul as a verb means “to hit,” but in time phrases like pukul tujuh it unambiguously means “o’clock.” Context removes the ambiguity.

Is alarm singular or plural? Do I need an article like “an”?

Indonesian has no articles. Alarm can be singular or plural from context. To be explicit:

Plural: beberapa alarm (several alarms), dua alarm (two alarms)
Reduplication (alarm-alarm) is possible but less common than using numbers/quantifiers.

How do I say “I haven’t set the alarm yet” or “I didn’t set the alarm”?

Not yet: Saya belum mengatur/setel alarm.
Didn’t (simple negation): Saya tidak mengatur/setel alarm. Use belum to imply it may still happen.

How formal is Saya? Can I use aku or gue?

Saya: neutral/formal; safe in most contexts.
Aku: informal/intimate with friends/family.
Gue: very colloquial Jakarta slang.
Example: Aku setel alarm jam tujuh. / Gue setel alarm jam tujuh.

Could I just say Saya setel alarm jam tujuh? Is that more natural?

Yes. Saya setel alarm jam tujuh or Saya pasang alarm jam tujuh are very common, natural ways to say this in everyday speech.

Any quick pronunciation tips?

Saya: SA-ya (y as in “yes”).
mengatur: me-NGA-tur (the ng is like “sing”).
untuk: un-tuk; final k is often a glottal stop (a quick throat catch).
pukul: PU-kul (both syllables clear).
tujuh: tu-JUH (the j like English “j”).
alarm: a-LARM (rolled/flapped r).

Why does atur become mengatur?

The root is atur (“arrange”). Adding the meN- prefix makes an active verb. Before a vowel like a-, meN- surfaces as meng-, giving mengatur.

Is there a polite way to ask someone to set an alarm for 7?

Use tolong (please):

Tolong setel/atur alarm untuk pukul tujuh.
Even shorter: Tolong setel alarm jam tujuh.