Adik perempuan saya membuka toples biskuit setelah makan malam.

In Indonesian, possessors usually come after the noun.

• adik perempuan saya = my younger sister
• literally: younger sibling female my

This is the normal pattern:

• rumah saya = my house
• buku mereka = their book
• ibu kami = our mother

So Indonesian does not usually copy the English order my younger sister.

Adik means younger sibling. By itself, it does not necessarily mean male or female.
To make it clear that the younger sibling is female, Indonesian adds perempuan:

• adik perempuan = younger sister
• adik laki-laki = younger brother

So this phrase is more literally female younger sibling.

Also note:

• adik = younger sibling
• kakak = older sibling

So if the person were an older sister, you would use kakak perempuan.

Yes, it could.
In many contexts, adik saya is enough, and people understand the gender from context.

But if the speaker wants to be explicit, they can say:

• adik perempuan saya = my younger sister
• adik laki-laki saya = my younger brother

So perempuan is added for clarity, not because adik always needs it.

Membuka is the active verb form built from the root buka (open).

A very common Indonesian pattern is:

• root: buka
• active verb with meN- prefix: membuka

In a normal formal sentence with a subject doing an action to an object, Indonesian often uses this meN- form:

• Dia membuka pintu. = He/She opened the door.
• Saya membaca buku. = I read a book.
• Mereka membeli makanan. = They bought food.

You may hear buka by itself in casual speech, commands, or shortened forms, but membuka is the standard full verb here.

It is part of the meN- active-verb prefix system. It marks the verb as an active action done by the subject.

With the root buka, the result is:

• buka = open
• membuka = to open / opens / opened, depending on context

The prefix changes shape depending on the first sound of the root. Here it becomes mem- before buka.

For a beginner, the most useful thing to remember is simply:

• membuka is the normal active form meaning to open

Toples biskuit is a noun + noun combination. It means a biscuit jar or a jar of biscuits, depending on context.

Indonesian often puts nouns together like this:

• toples biskuit = biscuit jar / jar of biscuits
• gelas kopi = coffee glass / cup of coffee
• toko buku = bookshop

The relationship between the two nouns is understood from context. Here, it most naturally means a jar containing biscuits.

You would not use dari here, because dari means from/of made from, so toples dari biskuit would sound like a jar made of biscuits, which is not the intended meaning.

Indonesian usually does not use articles like a, an, or the.

So:

• toples biskuit can mean a biscuit jar, the biscuit jar, or a jar of biscuits

The exact meaning comes from context.

This is very normal in Indonesian:

• Saya membeli buku. = I bought a book / the book
• Dia membuka pintu. = He/She opened a door / the door

If a speaker needs to be more specific, they can add other words, but often context is enough.

It can mean any of those, depending on context. Indonesian verbs do not change form for tense the way English verbs do.

So membuka itself does not tell you whether the action is:

• present: opens / is opening
• past: opened
• future: will open

Time is usually understood from context or from time words such as:

• kemarin = yesterday
• sekarang = now
• besok = tomorrow

In this sentence, if the translation shows a past event, that comes from context, not from a special past-tense verb form.

Because it is a time expression meaning after dinner or after eating dinner, and Indonesian often places time expressions after the main clause.

So the structure is:

• Adik perempuan saya = subject
• membuka = verb
• toples biskuit = object
• setelah makan malam = time phrase

This order is very natural in Indonesian.

You could also move time expressions in some cases for emphasis, but the version in the sentence is simple and standard.

It can be understood as either, and in many situations those meanings overlap.

• setelah = after
• makan malam = dinner / to eat dinner

So the phrase can function like:

• after dinner
• after having dinner
• after eating dinner

Indonesian often allows this kind of flexibility, especially with expressions built from verbs like makan.

It can behave like either, depending on context.

• As a noun, makan malam means dinner
• As a verbal idea, it can mean to eat dinner

In setelah makan malam, both readings fit naturally:

• after dinner
• after eating dinner

This is common in Indonesian. A form that looks verbal can also work very naturally as an event or activity noun without extra changes.

Because the subject is already fully stated as adik perempuan saya.

Indonesian does have pronouns such as:

• dia / ia = he/she

But once the sentence names the person directly, a pronoun is not needed.

So instead of saying something like My younger sister, she opened..., Indonesian simply says:

• Adik perempuan saya membuka...

That is the normal, straightforward structure.

Yes. Toples usually refers to a jar or a container, often one used for snacks, cookies, or biscuits.

So toples biskuit could be understood as:

• biscuit jar
• jar of biscuits
• sometimes more loosely, biscuit container

The best English choice depends on the translation style and the situation, but jar is very natural here.

Yes, it is natural and standard Indonesian.

It sounds like a normal complete sentence:

• clear subject
• standard active verb form
• natural object phrase
• natural time phrase

In very casual speech, people might shorten some parts, but the sentence as written is perfectly normal and grammatical.