Die kers is klein.

Here, die is the definite article, so it means the.

A useful thing to know is that Afrikaans uses die very broadly:

• die kers = the candle
• die kerse = the candles

Unlike some other languages, Afrikaans does not change the definite article for grammatical gender.

Yes. Kers is singular.

That can feel unusual to an English speaker, because English words ending in -s are often plural. In Afrikaans, though, a singular noun can naturally end in -s.

The plural of kers is kerse:

• die kers = the candle
• die kerse = the candles

Is is the present-tense form of to be in Afrikaans, from the infinitive wees.

In the present tense, Afrikaans uses is for all persons:

• Ek is = I am
• Jy is = you are
• Hy/Sy is = he/she is
• Ons is = we are
• Hulle is = they are

So Die kers is klein has a very familiar structure for English speakers.

Yes, in this simple sentence it is very similar to English:

• Die kers = subject
• is = verb
• klein = adjective/complement

So the pattern is:

subject + is + adjective

That is why the sentence feels quite straightforward.

Yes.

• die klein kers = the small candle

That is different from:

• Die kers is klein = The candle is small

So:

• die klein kers uses klein directly before the noun
• Die kers is klein uses klein after is to describe the noun

Both are correct; they just have different sentence structures.

You usually use the Afrikaans double negative:

Die kers is nie klein nie.

A simple way to think about it is:

• put one nie after the verb
• put another nie at the end of the clause

This double-nie pattern is very common in standard Afrikaans.

For a yes/no question, you usually put the verb first:

Is die kers klein?

This is similar to English Is the candle small?

So the statement:

• Die kers is klein.

becomes the question:

• Is die kers klein?

You would use the indefinite article 'n:

'n Kers is klein.

A very important writing point:

• 'n stays lowercase, even at the beginning of a sentence

So you write:

• 'n Kers is klein.

not:

• 'N kers is klein

You would say:

Die kerse is klein.

Notice two things:

• kers becomes kerse
• is stays is

So even with a plural subject, Afrikaans still uses is in the present tense.

A rough English-friendly guide is:

dee kers iss klayn

Word by word:

• die ≈ dee
• kers ≈ kers / kehrs
• is ≈ iss
• klein ≈ klayn or kline

This is only an approximation, but it is a good starting point for a learner.