Die optrede vind buite plaas.

Die is the definite article in Afrikaans, so here it means the.

A useful thing for English speakers to know is that Afrikaans does not change the definite article for gender or number. So die can mean:

• the performance
• the performances
• the man
• the woman

Unlike Dutch or German, there is just one common form: die.

Optrede usually means a performance, appearance, or act in the sense of someone appearing before an audience.

Depending on context, it can refer to things like:

• a stage performance
• a musical performance
• a public appearance
• an official action or conduct

In this sentence, it most naturally means the performance.

Because plaasvind is a separable verb in Afrikaans.

Its dictionary form is:

• plaasvind = to take place / to happen / to be held

But in a main clause, the verb often splits:

• Die optrede vind buite plaas.

Here:

• vind is the finite verb and comes earlier in the sentence
• plaas goes to the end

This is very similar to separable verbs in Dutch and German.

Yes. Plaasvind or separated vind ... plaas is a very common fixed expression meaning:

• take place
• happen
• be held

It is not usually understood literally as English find place. Even though the words resemble that literally, learners should treat it as one unit of meaning.

Examples:

• Die vergadering vind môre plaas.
  The meeting takes place tomorrow.

• Die fees het Saterdag plaasgevind.
  The festival took place on Saturday.

Because plaas belongs to the separable verb plaasvind, and in a main clause that final part often goes at the end.

So the sentence structure is roughly:

• Die optrede = subject
• vind = finite verb
• buite = adverb
• plaas = separated final part of the verb

That is why buite appears before plaas.

Afrikaans often puts adverbs before the separated particle at the end:

• Die klas begin môre weer.
• Die byeenkoms vind hier plaas.

Here buite means outside or outdoors.

It is functioning adverbially, describing where the event takes place.

Compare:

• Die kinders speel buite.
  The children are playing outside.

• Ons wag buite.
  We are waiting outside.

In other contexts, buite can also be used with nouns or in expressions involving location, but in this sentence it simply means outside.

You could, but it means something slightly different.

• Die optrede vind buite plaas.
  The performance takes place outside.
  This focuses on where the event is held.

• Die optrede is buite.
  The performance is outside.
  This can work in some contexts, but it sounds less explicit and may feel more like a statement about location than about the event being held there.

So vind ... plaas is the more natural choice when talking about an event occurring or being held somewhere.

A common past form is:

• Die optrede het buite plaasgevind.

Here:

• het is the auxiliary
• plaasgevind is the past participle form

Notice that in the past tense, the separated verb is usually written together again in the participle:

• present: vind ... plaas
• past participle: plaasgevind

So:

• Die optrede vind buite plaas.
• Die optrede het buite plaasgevind.

A natural future version is:

• Die optrede sal buite plaasvind.

Here, because of sal, the full infinitive plaasvind stays together at the end.

Compare:

• present: Die optrede vind buite plaas.
• future: Die optrede sal buite plaasvind.

That pattern is very common with separable verbs in Afrikaans.

No, much less than in English.

In this sentence, vind stays the same regardless of the subject in normal present-tense use. Afrikaans verbs usually do not change form for I, you, he, they, and so on.

For example:

• Ek vind dit vreemd.
• Hy vind dit vreemd.
• Hulle vind dit vreemd.

So learners do not need to memorize lots of present-tense endings.

A rough guide for an English speaker:

• optrede: roughly OP-tray-duh
• vind: roughly fint or vint depending on accent
• plaas: roughly plahs

A few helpful notes:

• aa in plaas is a long vowel
• the g sound is not in this sentence, so pronunciation is fairly approachable
• the final e in optrede is usually a light uh sound, not a strong ee

Pronunciation varies by speaker, but that rough guide will get you close enough to be understood.