Learn Hardcore Malay: Kempen derma darah di kampus itu menarik ramai sukarelawan muda. - The blood donation campaign at that campus attracts many young volunteers.

A verb: to attract / to draw in
- Kempen itu menarik ramai orang.
  = The campaign attracted many people.
An adjective: interesting / attractive
- Kempen itu sangat menarik.
  = The campaign is very interesting.

In your sentence, menarik is followed by an object (ramai sukarelawan muda), so it’s clearly a verb:
“(It) attracted many young volunteers.”

When menarik is followed by a noun phrase that looks like the “thing being attracted”, or by minat (interest), it’s usually the verb “to attract”:

Kempen itu menarik minat ramai pelajar.
= The campaign attracted the interest of many students.

What does derma mean here? Is derma darah like a verb phrase or a noun?

Derma can be both a noun (donation) and a verb (to donate).

In kempen derma darah:

kempen = campaign
derma darah = blood donation

Here, derma darah works together like a compound noun, describing the type of campaign:

kempen derma darah = blood donation campaign

If you wanted to be more clearly verbal, you could also say:

kempen menderma darah
(campaign to donate blood)

But in everyday usage, kempen derma darah (noun–noun) is very natural and common.

Why is it kempen derma darah, not kempen darah derma or something else? What’s the word order rule?

Malay typically uses “head noun + modifier” order.

kempen (head noun: campaign)
derma darah (modifier: what kind of campaign?)

So the pattern is:

[Type of thing] + [detail / of-phrase]

Comparable to English “blood donation campaign” (not “campaign blood donation”).

Other examples:

kempen kebersihan = cleanliness campaign
kempen keselamatan jalan raya = road safety campaign

What exactly does di kampus itu modify? The campaign, or the volunteers?

Di kampus itu attaches to the nearest suitable noun phrase before it, which is kempen derma darah.

So the most natural reading is:

kempen derma darah di kampus itu
= the blood donation campaign on that campus

If you wanted to say the volunteers are on that campus (rather than the campaign being held there), you’d usually change the structure, for example:

Kempen derma darah itu menarik ramai sukarelawan muda di kampus itu.
(now di kampus itu is closer to sukarelawan muda and likely modifies them)

Why itu and not ini in di kampus itu?

Ini and itu mark proximity or known-ness:

ini = this (near the speaker, or just-introduced)
itu = that (farther away, or already known / previously mentioned / specific)

Di kampus itu often implies:

a specific campus both speaker and listener already know,
or
a campus that has been mentioned earlier in the conversation/text.

If the speaker is physically on the campus while speaking, you might hear:

di kampus ini = on this campus (where we are now)

How does ramai work? Why not banyak sukarelawan?

Both ramai and banyak relate to “many / a lot of”, but they are used differently:

ramai → mainly used for people
- ramai sukarelawan = many volunteers
- ramai pelajar = many students
banyak → used for things, uncountable nouns, or more general quantities
- banyak buku = many books
- banyak masa = a lot of time

So ramai sukarelawan muda is the natural choice because sukarelawan are people.

Why is there no plural marking like sukarelawan-sukarelawan? How do I know it’s plural?

Malay usually does not mark plural nouns explicitly when quantity words like ramai, banyak, beberapa, etc. are present.

In this sentence:

ramai sukarelawan muda
literally: many volunteer young

Ramai already tells you it’s more than one, so you don’t need to repeat the noun.

Other options (all acceptable but slightly different in style/emphasis):

ramai sukarelawan muda (most natural, everyday)
para sukarelawan muda (more formal/literary “the volunteers”)
ramai para sukarelawan muda (possible, quite formal and emphatic)
sukarelawan-sukarelawan muda (reduplication for emphasis or clarity, often in writing)

Why is it sukarelawan muda, not muda sukarelawan? What is the rule for adjectives?

In Malay, descriptive adjectives normally come after the noun:

sukarelawan muda = young volunteers
pelajar rajin = diligent student
bangunan tinggi = tall building

So the pattern is:

[Noun] + [Adjective]

If you say muda sukarelawan, it sounds wrong or ungrammatical to a native speaker in this context.

Does this sentence mean the campaign is currently attracting people, or that it already attracted them? I don’t see any tense like past or present.

Malay verbs generally do not change form for tense. Context tells you whether the event is past, present, or future.

Menarik on its own is neutral:

It can mean “attracts / is attracting” (present)
or “attracted” (past)

To be more explicit, you can add time/aspect words:

telah menarik / sudah menarik
= has attracted / attracted (completed)
sedang menarik
= is attracting (in progress now)
akan menarik
= will attract

Your original sentence can be translated in context as either “attracted” or “attracts”, depending on the surrounding information.

Could I use the passive voice here, like “Many young volunteers were attracted by the blood donation campaign”?

Yes, Malay has passive-like structures, but they sound different from English. Two common patterns:

Using ter- (stative/passive-ish nuance):
- Ramai sukarelawan muda tertarik dengan/oleh kempen derma darah di kampus itu.
  = Many young volunteers were / are attracted to the blood donation campaign on that campus.
Using di- passive is less usual with menarik for this meaning, but structurally possible in some contexts. Native speakers more often use tertarik for “being attracted (to something)”.

So your original:

Kempen derma darah di kampus itu menarik ramai sukarelawan muda.
(campaign as subject, active voice)

Passive-ish alternative focusing on the volunteers:

Ramai sukarelawan muda tertarik dengan kempen derma darah di kampus itu.

Is there any difference between kampus and universiti here? Could I say di universiti itu instead?

You can say di universiti itu, but it slightly changes the nuance:

kampus = campus (the physical grounds, buildings, environment)
universiti = university (the institution; can also imply the place)

In everyday speech, they often overlap.
Kempen derma darah di kampus itu tends to emphasize the on-campus location (student area, campus grounds), while di universiti itu sounds a bit more like “at that university” as an institution or as a general place.

Both would usually be understood similarly, and both are grammatically fine.