Learn Hardcore Indonesian: Kami membaca jadwal di papan pengumuman. - We read the schedule on the bulletin board.

Baca is the root; the active transitive form uses the prefix meN-, which becomes mem- before words starting with b: mem + baca → membaca. In casual speech you may hear the bare root after a pronoun (e.g., Aku baca buku), but with kami the neutral/formal choice is membaca.

Do I need the English articles the or a before jadwal?

No. Indonesian has no articles. Jadwal can mean either a schedule or the schedule. To be specific:

that schedule: jadwal itu
this schedule: jadwal ini Using sebuah jadwal is rare; use numbers/quantifiers only when you’re really counting: satu jadwal, beberapa jadwal.

Is jadwal singular or plural here?

Number is usually unmarked and inferred from context. If you need to mark it:

Plural: jadwal-jadwal, or use a quantifier (beberapa jadwal, semua jadwal).
Singular-specific: add a demonstrative (jadwal itu/ini).

What does di mean here—on, at, or in?

Di marks location and can correspond to on/at/in. Di papan pengumuman is naturally on the notice board. For movement, use ke (to) and dari (from).

Can I use pada instead of di?

For physical locations, use di. Pada is more formal and used with time expressions and abstract relations (e.g., pada hari Senin, pada situasi ini) or, with people, typically kepada. Pada papan pengumuman is grammatical but sounds stilted; di papan pengumuman is the natural choice.

What exactly is papan pengumuman?

Literally announcement board, i.e., a notice/bulletin board.

papan = board
pengumuman = announcement(s) Synonyms: papan informasi (info board). Informal school term: mading (from majalah dinding, wall magazine).

Does di papan pengumuman tell where we read, or which schedule we read?

It’s ambiguous. Most readers take it as the schedule that is on the board. To be explicit:

Which schedule: Kami membaca jadwal yang ada di papan pengumuman.
Where we read: Kami membaca jadwal itu di depan papan pengumuman.

How do I say we are reading it right now or we already read it?

Right now: Kami sedang membacanya di papan pengumuman.
Already: Kami sudah membacanya di papan pengumuman. Here -nya = it, attached to the verb.

Can I drop the subject kami?

Yes, in context you can say Membaca jadwal di papan pengumuman and the subject will be understood. In neutral/formal writing, it’s clearer to keep the pronoun.

Is di here the same as the passive prefix di-?

No. Here di is a separate preposition meaning at/on/in. The passive prefix di- attaches to verbs (no space), e.g., dibaca = is/was read: Jadwal itu dibaca (oleh) kami di papan pengumuman.