Learn Hardcore Indonesian: Setiap akhir pekan saya menyortir catatan, menandai ide penting dengan stabilo, lalu menghapus file yang tidak perlu. - Every weekend I sort my notes, mark important ideas with a highlighter, then delete files that are not needed.

Setiap akhir pekan saya menyortir catatan, …
Saya menyortir catatan, menandai ide penting dengan stabilo, lalu menghapus file yang tidak perlu setiap akhir pekan.

Differences in feel:

At the beginning, setiap akhir pekan is emphasized as the time frame.
At the end, it feels like a summarizing time expression covering the whole sequence.

Both are natural. The original is a very common word order.

Why is saya used? Could I use aku here?

Saya and aku both mean I.

Saya: more neutral/polite, common in formal and semi-formal situations, writing, talking to strangers, etc.
Aku: more informal/intimate, used with friends, family, or people your age in casual settings.

So you could say:

Setiap akhir pekan saya menyortir catatan… (neutral/polite)
Setiap akhir pekan aku menyortir catatan… (more casual/intimate)

Grammatically both are correct; it’s a choice of register.

What exactly does menyortir mean? Is it the same as mengurutkan or merapikan?

Menyortir means to sort, especially to separate or classify things into groups or categories.

Comparison:

Menyortir catatan
= sorting notes (e.g., by topic, importance, date).
Mengurutkan catatan
= ordering notes (e.g., putting them in sequence, like by time or priority).
Merapikan catatan
= tidying up / organizing notes (more general, making them neat).

In this sentence, menyortir catatan suggests you are going through your notes and dividing or arranging them in some systematic way, not just making them neat.

Is catatan singular or plural? How would I say notes vs a note?

Indonesian nouns usually do not change form for singular vs plural. Context tells you.

catatan can mean note or notes.
Here, menyortir catatan is naturally understood as sorting notes (plural).

To explicitly show plurality, you can use:

Reduplication: catatan-catatan
A quantity word: banyak catatan (many notes), beberapa catatan (several notes)

But often, simple catatan is enough, as in this sentence.

What does menandai ide penting dengan stabilo literally mean?

Word by word:

menandai = to mark
ide penting = important ideas
dengan stabilo = with a highlighter

So literally: to mark important ideas with a highlighter.

menandai comes from tanda (mark, sign) + prefix meN-, forming a verb to mark.
dengan introduces the tool/instrument you use.
stabilo in Indonesian is commonly used to mean highlighter (it started as a brand name, like Stabilo).

What is stabilo? Is it a general word for highlighter?

Yes. Stabilo is originally a brand name (like the company STABILO), but in Indonesian:

stabilo (lowercase s) is widely used as a generic term for a highlighter pen.

So menandai ide penting dengan stabilo = marking important ideas with a highlighter.

More neutral/less brand-like options would be:

pena stabilo (highlighter pen)
spidol stabilo (highlighter marker)

What is the function of lalu in this sentence? Could I use kemudian or dan kemudian instead?

Lalu connects actions in a sequence, similar to then or after that.

In the sentence:

…menyortir catatan, menandai ide penting dengan stabilo, lalu menghapus file yang tidak perlu.

It signals that menghapus file yang tidak perlu is the next step after the previous actions.

You can replace it with:

kemudian (then, afterwards)
dan kemudian (and then)

For example:

…, menandai ide penting dengan stabilo, kemudian menghapus file yang tidak perlu.
…, menandai ide penting dengan stabilo, dan kemudian menghapus file yang tidak perlu.

All are natural; lalu is a bit shorter and very common in storytelling or step-by-step descriptions.

Why do we say menghapus file yang tidak perlu and not just menghapus file tidak perlu? What does yang do?

Yang introduces a relative clause or a descriptive phrase that narrows down which thing we are talking about.

file yang tidak perlu
= the files that are not necessary / that are unnecessary.

If you say file tidak perlu without yang, it sounds incomplete or awkward in this context. Normally, when an adjective is logically describing or identifying the noun in this kind of phrase, you use yang.

Patterns:

orang yang sabar = a person who is patient
buku yang penting = the book that is important
file yang tidak perlu = files that are unnecessary

So here, yang is required for natural, correct grammar.

Why is ide penting in that order? Can I say penting ide?

In Indonesian, adjectives usually come after the noun.

ide penting
= important idea(s)
(noun ide
- adjective penting)

Penting ide is not correct.

Some common patterns:

buku baru = new book
rumah besar = big house
kendaraan cepat = fast vehicle

So ide penting follows the standard noun + adjective order.

Why are commas used between the verbs? Could I use dan instead?

The commas are separating a series of actions:

menyortir catatan
menandai ide penting dengan stabilo
lalu menghapus file yang tidak perlu

This is similar to English:
I sort my notes, highlight important ideas, then delete unnecessary files.

You can also use dan:

…saya menyortir catatan dan menandai ide penting dengan stabilo, lalu menghapus file yang tidak perlu.
Or: …saya menyortir catatan, menandai ide penting dengan stabilo, dan menghapus file yang tidak perlu.

All are acceptable. The original style with commas feels smooth and natural, especially in writing.

What is the difference between menghapus and the base form hapus? Could I say saya hapus file?

Hapus is the base form (root) meaning erase / delete.
Menghapus is the verb form with the prefix meN-, meaning to delete / to erase (doing the action).

In standard Indonesian, especially in formal or neutral sentences, you generally use the meN- form:

Saya menghapus file yang tidak perlu.

In casual speech, people often drop the prefix and use the base form after a pronoun:

Saya hapus file yang tidak perlu.
Aku hapus file yang tidak perlu.

Both are understood. The version with menghapus is more standard and neutral; saya hapus sounds more informal/colloquial.

Is file a normal Indonesian word, or is there another word like berkas?

File is very commonly used in Indonesian, especially for computer files.

There is also berkas, which can mean file / dossier / document, often in more formal or administrative contexts (paper documents, case files, etc.).

In this sentence, for digital context:

menghapus file yang tidak perlu
is the most natural modern phrasing.

You could say menghapus berkas yang tidak perlu, but it sounds a bit more formal or old-fashioned for computer usage, depending on the context.