Platemessen har bruktplater.

Platemessen means the record fair.

It is built from:

• plate = record
• messe = fair / exhibition / trade fair

So:

• platemesse = record fair
• platemessen = the record fair

In this sentence, plate does not mean a food plate. In Norwegian, plate can also mean a music record.

Because Norwegian usually writes compound nouns as one word.

So:

• plate
  • messe → platemesse

This is very common in Norwegian. Where English often writes two words, Norwegian often prefers one compound word.

The ending -n makes the noun definite.

So:

• platemesse = a record fair
• platemessen = the record fair

This is a normal pattern for many masculine nouns in Norwegian:

• en bil = a car
• bilen = the car

Likewise:

• en platemesse = a record fair
• platemessen = the record fair

Har means has.

It is the present tense of å ha = to have.

So:

• Platemessen har bruktplater = The record fair has used records

In natural English, the idea may be closer to The record fair has second-hand records for sale or There are used records at the record fair, but grammatically har simply means has.

Bruktplater means used records or second-hand records.

It is also a compound noun:

• brukt = used / second-hand
• plater = records

So:

• en bruktplate = a used record
• bruktplater = used records

Yes. Brukt is the past participle of å bruke, which usually means to use.

Examples:

• å bruke = to use
• jeg har brukt den = I have used it

In front of a noun, brukt often means used in the sense of not new:

• en bruktbil = a used car
• bruktklær = used clothes
• bruktplater = used records

Because Norwegian often has no article in the indefinite plural.

Compare:

• en bruktplate = a used record
• bruktplater or more naturally bruktplater = used records

This is like:

• I bought books not
• I bought some books
  even though English often allows both.

So in the sentence:

• Platemessen har bruktplater

the noun bruktplater is indefinite plural: used records.

Because plater is the plural of plate when plate means record.

So:

• en plate = a record
• plater = records

That gives:

• bruktplate = used record
• bruktplater = used records

This is the normal Norwegian main-clause word order:

subject + verb + object

So:

• Platemessen = subject
• har = verb
• bruktplater = object

This matches basic English word order:

• The record fair has used records

Yes. Depending on what nuance you want, there are other possibilities.

For example:

• Det finnes bruktplater på platemessen. = There are used records at the record fair.
• På platemessen er det bruktplater. = At the record fair, there are used records.

But Platemessen har bruktplater is a perfectly understandable and natural way to say that the fair has used records available.

A rough English-friendly guide would be:

PLAH-teh-mess-en har BROOKT-plah-ter

A few notes:

• plate starts with a broad a, not like English plate
• messe has a short e sound
• brukt has a short u, somewhat like the vowel in put, but not exactly
• plater ends with a light -er

Exact pronunciation depends a bit on dialect, but this approximation is a useful start.

Usually, yes, or at least about music records in general.

In Norwegian, plate can mean:

• a physical plate
• a music record
• sometimes more generally an album, depending on context

Because the sentence mentions platemessen (the record fair), the meaning is clearly about music records, especially physical ones such as vinyl.

Normally, no.

In Norwegian, common nouns are not capitalized unless they begin the sentence.

So normally you write:

• platemessen
• bruktplater

In your sentence, Platemessen is capitalized only because it is the first word of the sentence.