Learn Hardcore Norwegian: Butikken har et kort kurs om trygg bruk av varmeovner og vifter. - The store has a short course on the safe use of heaters and fans.

har et kurs: neutral, everyday phrasing meaning “has/offers a course available.”
tilbyr et kurs: “offers a course” (more formal/marketing register).
holder et kurs: “holds/conducts a course” (focus on running the sessions).
arrangerer et kurs: “organizes a course” (focus on arranging/planning it).

Why is it et kort kurs and not en kort kurs?

Because kurs is a neuter noun in Bokmål. Indefinite singular neuter takes the article et, so you get et kurs. The adjective agrees with the neuter noun: many adjectives add -t in neuter indefinite, but kort already ends in -t, so it stays kort. In the definite form it becomes det korte kurset.

Could I say et lite kurs instead of et kort kurs?

Yes, but there’s a nuance:

et kort kurs = short in duration (time).
et lite kurs = small in scope/size (few topics/participants). It can also imply short, but it primarily targets size/extent.

Should it be kurs i rather than kurs om?

Both are correct:

kurs i X is the most idiomatic for “a course in X” (skill/competence-oriented).
kurs om X is “a course about X” (information/topic-oriented). Here, et kort kurs i trygg bruk av varmeovner og vifter would be very natural; om also works.

Why trygg bruk and not sikker bruk?

Both exist, but they differ slightly:

trygg = safe (people feel safe; absence of danger).
sikker = safe/secure/certain (more technical/formal). With bruk, both are possible. In safety guidelines, sikker bruk might sound a bit more technical; trygg bruk is also idiomatic and common.

Why is it trygg bruk and not trygt bruk or trygge bruk?

bruk is a common-gender noun used here as a mass noun, so the adjective is the indefinite singular common-gender form: trygg bruk.
trygt is the neuter form (wouldn’t match bruk).
trygge is used with definite nouns or plurals: den trygge bruken (“the safe use”).

What does av do in bruk av varmeovner og vifter? Could I use på or med?

In this construction, bruk av + noun means “use of + noun,” and av is the required preposition. Alternatives change the meaning:

bruk på = use on (a surface/location).
bruk med = use with (together with something). So for “use of heaters and fans,” you need bruk av varmeovner og vifter.

Are varmeovner and vifter the correct plurals? What are the singular and definite forms?

Yes. Forms:

varmeovn (a space heater): en varmeovn, varmeovnen, varmeovner, varmeovnene.
vifte (a fan): en/ei vifte, viften/vifta, vifter, viftene. Note that vifte is feminine, but in Bokmål you may also treat it as common gender (masculine), hence both en vifte / viften and ei vifte / vifta are acceptable.

Why are the device nouns plural? Could I use the singular to speak generally?

Indefinite plural is a natural way in Norwegian to talk about a class of items in general: bruk av varmeovner og vifter = “use of heaters and fans (in general).” Singular for a generic class is less idiomatic here. You could also keep it generic with plural definite if already specified, but the indefinite plural is the cleanest for general reference.

Is varmeovn written as one word? Why not varme ovn?

Yes, it’s one compound word: varmeovn. Norwegian generally writes compounds together (or with a hyphen in specific cases). Splitting it (varme ovn) would be incorrect and can be confusing.

Why is it Butikken (the shop) and not en butikk (a shop)?

Butikken is the definite form, so it refers to a specific, known shop (for example, one already mentioned in context). Forms: en butikk (indefinite), butikken (definite).

Is the word order standard here?

Yes. It’s regular S–V–O with post-modifiers:

Subject: Butikken
Verb: har
Object: et kort kurs
PP modifying “kurs”: om trygg bruk
PP complementing “bruk”: av varmeovner og vifter Everything sits where Norwegian expects it, and moving the prepositional phrases earlier would sound marked or clumsy.

What are the plural rules for kurs? I sometimes see people write kurser.

For the noun kurs (a course), the standard plural is unchanged in the indefinite:

Singular: et kurs
Indefinite plural: kurs
Definite plural: kursene Writing kurser as the plural of the noun is nonstandard. Note that kurser does exist as a verb form of å kurse (“to train someone”): e.g., “Bedriften kurser ansatte” (“The company trains employees”).