Learn Hardcore Malay: Semalam, kipas baru dipasang di bilik saya. - Yesterday, a new fan was installed in my room.

In Malay you can start a sentence with a time-adverb like semalam (“yesterday”) to set the temporal context early. The comma after semalam is purely optional—aids readability but isn’t grammatically required. You can write either:
• Semalam, kipas baru dipasang di bilik saya.
• Semalam kipas baru dipasang di bilik saya.

How is the passive voice formed in Malay, as in dipasang?

Malay creates the passive by adding the prefix di- directly to the verb root (here pasang → dipasang = “was installed”). In passive clauses you often omit the agent, but if you want to include it you use oleh (“by”):
• Semalam, kipas baru dipasang oleh tukang paip di bilik saya.

How do I tell the difference between the prefix di- in dipasang and the preposition di in di bilik saya?

In writing, the passive prefix di- is attached to the verb without a space (dipasang). The preposition di (“in/at”) stands alone, followed by a space and then the location (di bilik saya). Context and spacing are your clues.

What role does baru play in kipas baru dipasang? Does it mean “new” or “just recently”?

Here baru is an adjective modifying kipas, so it means “new fan.” Malay places descriptive adjectives after the noun. If you instead want “the fan was just installed,” you’d treat baru as an adverb (often adding sahaja or saja) and move it nearer the verb:
• Semalam, kipas dipasang baru sahaja di bilik saya.

In Malay, why does the adjective baru follow the noun kipas instead of appearing before it like in English?

By default Malay adjectives come after the noun they describe. So you always say kipas baru (fan new). Unlike English, you don’t put the adjective before the noun.

Why is the possessor saya placed after bilik instead of before it?

Malay uses a noun-then-possessor order: bilik saya literally “room my.” There’s no genitive ’s or possessive suffix; the possessor simply follows the noun.

How can I convert this sentence into active voice or mention who installed the fan?

Use an active verb and a subject. For example:
• Semalam, tukang paip memasang kipas baru di bilik saya.
Or keep passive but add the agent:
• Semalam, kipas baru dipasang oleh tukang paip di bilik saya.