Learn Hardcore Indonesian: Saya menaruh saus di meja.

Past: Tadi/barusan saya menaruh saus di meja. (I put it earlier/just now.)
Completed: Saya sudah menaruh saus di meja. (I have already put it.)
Progressive: Saya sedang menaruh saus di meja. (I am putting it.)
Future: Saya akan menaruh saus di meja. (I will put it.)

What’s the difference between menaruh, meletakkan, and menempatkan?

menaruh: very common, neutral “to put/place” (everyday speech).
meletakkan: also “to put/place,” slightly more formal/literal “to lay/put down,” often preferred in writing/instructions.
menempatkan: “to allocate/position/place” (more formal/abstract or for arranged placement, e.g., staff, furniture layout).

Can I say Saya taruh saus di meja or Saya naruh saus di meja?

Saya taruh … = “short active” form (base verb without the prefix) used a lot in everyday speech. Natural but less formal than menaruh.
Saya naruh … = very colloquial; common in casual conversation, not for formal writing.
Formal/neutral writing: Saya menaruh … or Saya meletakkan ….

Does menaruh need an object?

Yes. It’s transitive. You normally must say what you put:

Natural: Saya menaruh saus di meja.
Unnatural: Saya menaruh di meja. (What did you put?) If the object is understood, use a pronoun/marker: Saya menaruhnya di meja.

What exactly does di mean here? How is it different from ke and dari?

Should I say di meja or di atas meja for “on the table”?

Both occur:

di meja is common in speech and often understood as “on the table” by context.
di atas meja literally means “on top of the table” and is the clearest/most explicit way to say “on (the surface of) the table.” If you need to be explicit, choose di atas meja.

How do I say “onto the table” (emphasizing movement onto the surface)?

Use a verb of placing + the final location:

Most natural: (Saya) menaruh/meletakkan saus di atas meja. Using ke atas meja sounds more like movement “to up onto” and pairs better with motion verbs: (Saya) membawa saus ke atas meja, melempar ke atas meja. With “put/place,” di atas meja is standard.

What’s the difference between di (preposition) and the passive prefix di-?

di (preposition) is written separately before a noun: di meja.
di- (passive prefix) attaches to a verb: ditaruh, diletakkan. Tip: If it’s followed by a noun, it’s the preposition (di meja). If it’s glued to a verb, it’s the passive (ditaruh).

How do I make this sentence passive?

Several options:

Standard passive: Saus ditaruh di meja (oleh saya). (by me is usually omitted unless needed)
Passive with agent after the verb (colloquial): Saus ditaruh saya di meja.
“Short active” with fronted object: Saus(‑nya) saya taruh di meja. (very common in speech)

How do I specify “the sauce,” “that sauce,” or “a bottle of sauce”?

“the sauce” (context-known): sausnya or saus itu
“that sauce” (pointing/contrast): saus itu
Indefinite/quantity: sebotol saus (a bottle of sauce), sachet saus/sebungkus saus (a sachet/packet), sedikit saus (a little sauce)

How do I negate it?

Use tidak for verbs/adjectives; belum means “not yet”:

Saya tidak menaruh saus di meja. (I didn’t/don’t put the sauce on the table.)
Saya belum menaruh saus di meja. (I haven’t put the sauce on the table yet.)

Can I drop the subject Saya?

Yes, if context makes it clear, especially in conversation:

As a statement, dropping the subject with menaruh sounds odd. Better: Saya taruh saus di meja. or Sausnya saya taruh di meja.
As an instruction/command, you drop it: Taruh saus di meja!

Any pronunciation tips for these words?

saya: SA-ya (two syllables; y like “y” in “yes”)
menaruh: me-NA-ruh (tap/trill the r; stress tends to be on NA)
saus: commonly pronounced as two syllables SA-US; in casual speech you may also hear it compressed (similar to “sos”)
di: “dee”
meja: ME-ja (j like “j” in “judge”)