Die verfspat en verfskraper is op die dekseil.

Because in Afrikaans, the present tense of wees (to be) is is for all persons and numbers.

So you get:

• ek is = I am
• jy is = you are
• hy/sy is = he/she is
• ons is = we are
• hulle is = they are

That means Die verfspat en verfskraper is op die dekseil is normal Afrikaans. English changes from is to are, but Afrikaans does not.

In Afrikaans, one definite article can cover two nouns joined by en if both are meant as definite items in the same phrase.

So:

• Die verfspat en verfskraper = the paint splatter and paint scraper

You can also say:

• Die verfspat en die verfskraper

That version is a bit more explicit. Both are possible. The version with one die is simply more compact.

Die can be both singular and plural in Afrikaans. It is the normal definite article for the.

Examples:

• die boek = the book
• die boeke = the books

So in this sentence, die is being used with singular nouns, but the form would look the same in the plural.

Also, Afrikaans does not have grammatical gender like German or Dutch, so die does not change for masculine, feminine, or neuter nouns.

Afrikaans usually writes compound nouns as one word.

So:

• verf
  • spat → verfspat
• verf
  • skraper → verfskraper
• dek
  • seil → dekseil

This is very common in Afrikaans and also in Dutch and German. English often writes similar ideas as two words or with a hyphen, but Afrikaans strongly prefers a single compound word.

Op here means on.

So:

• op die dekseil = on the tarpaulin / on the drop cloth

Unlike in some languages, the noun after the preposition does not change form because of op. Afrikaans does not have a case system like German, so the phrase stays simple:

• op die tafel = on the table
• op die vloer = on the floor
• op die dekseil = on the tarpaulin

Afrikaans main clauses usually follow the verb-second pattern. That means the finite verb comes early in the sentence, typically in second position.

In this sentence:

• Die verfspat en verfskraper = subject
• is = finite verb
• op die dekseil = prepositional phrase

So the normal order is:

• Die verfspat en verfskraper is op die dekseil.

You can move the location phrase to the front for emphasis:

• Op die dekseil is die verfspat en verfskraper.

That is grammatical, but the original order is the most neutral.

Yes, sometimes.

• is gives a simple statement of location: they are on the tarpaulin.
• lê can sound more physical or visual, as in are lying on the tarpaulin.

So you might hear:

• Die verfspat en verfskraper is op die dekseil.
• Die verfspat en verfskraper lê op die dekseil.

Both can work, but lê is often used when objects are literally lying somewhere. Is is more general and perfectly acceptable.

Die means the, so it points to specific, identifiable things.
'n means a/an, so it introduces something non-specific.

Compare:

• Die verfspat en verfskraper is op die dekseil.
  = the paint splatter and the paint scraper are on the tarpaulin

• 'n Verfspat en 'n verfskraper is op 'n dekseil.
  = a paint splatter and a paint scraper are on a tarpaulin

So the sentence with die suggests the speaker has particular items in mind.

It is grammatical and understandable. A native speaker could definitely say it.

That said, depending on context, a speaker might choose a slightly different wording:

• Die verfspat en die verfskraper is op die dekseil.
  More explicit, because each noun gets its own die.

• Daar is 'n verfspat en 'n verfskraper op die dekseil.
  More natural if you are simply noticing or introducing them.

• Die verfskraper lê op die dekseil.
  More natural if the focus is especially on the physical location of the scraper.

So the original sentence is fine, but there are other natural ways to express the same basic idea.