Die tegnikus aktiveer die veselverbinding.

Because die means the in Afrikaans, and each definite noun here has its own article:

• die tegnikus = the technician
• die veselverbinding = the fiber connection

Unlike English learners might expect from some other languages, Afrikaans uses die for all genders, and also for singular and plural definite nouns in most ordinary cases.

No. Afrikaans does not assign grammatical gender to nouns the way languages like German do. So tegnikus and veselverbinding do not take different articles based on masculine, feminine, or neuter gender.

That is why you simply use die for both nouns.

Afrikaans verbs usually do not change form for different subjects in the present tense. That is much simpler than English.

For example:

• Ek aktiveer = I activate
• Jy aktiveer = you activate
• Die tegnikus aktiveer = the technician activates
• Hulle aktiveer = they activate

So aktiveer stays the same.

Yes, in this sentence it is. The structure is:

• Die tegnikus = subject
• aktiveer = verb
• die veselverbinding = object

So it follows normal subject–verb–object order, just like English:

• The technician activates the fiber connection.

That said, Afrikaans word order can change in other sentence types, especially when another element comes first or in subordinate clauses.

It is the simple present form. In Afrikaans, the simple present can often cover meanings that English expresses in different ways, depending on context.

So this sentence could mean:

• The technician activates the fiber connection.
• The technician is activating the fiber connection.
  sometimes, if the context supports that reading

If you want to be more explicitly progressive, Afrikaans often uses a structure like:

• Die tegnikus is besig om die veselverbinding te aktiveer.

But the simple present sentence is completely normal.

Yes. Afrikaans commonly forms compound nouns as a single word.

Here:

• vesel = fiber
• verbinding = connection

Together:

• veselverbinding = fiber connection

This is very common in Afrikaans. The final part usually tells you the main category of the thing:

• verbinding is the core noun
• vesel describes what kind of connection it is

So it is literally a fiber-connection.

Yes, it is a close cognate. Many technical or academic words in Afrikaans resemble English words, although spelling may differ.

• tegnikus = technician
• aktiveer = activate
• verbinding can mean connection

This can make technical Afrikaans easier for English speakers, but you should still watch out for pronunciation and for words that only partly overlap in meaning.

A rough English-friendly guide is:

• tegnikus ≈ tekh-nee-kus
• aktiveer ≈ ak-ti-VEER
• veselverbinding ≈ VAY-sel-fer-BIN-ding or FEH-sel-ver-BIN-ding, depending on accent and how narrowly you want to approximate it

A few helpful points:

• g in Afrikaans is usually a throaty sound, not the English g in go
• v is often pronounced close to English f
• ee is usually a long vowel sound

Pronunciation varies somewhat by speaker and region, so these are only rough guides.

Because this is a normal main clause with the subject first. In standard Afrikaans main clauses, the finite verb usually comes early, often in the second position.

So:

• Die tegnikus aktiveer die veselverbinding.

However, if another element comes first, the verb still stays in the second position:

• Vandag aktiveer die tegnikus die veselverbinding.
  = Today the technician activates the fiber connection.

In subordinate clauses, the verb placement can be different.

No. Unlike German, Afrikaans does not capitalize all nouns.

So you write:

• die tegnikus
• die veselverbinding

Only the first word of the sentence and proper names are capitalized in normal writing.

You would change the noun, not the article die.

Examples:

• die tegnici = the technicians
• die veselverbindings = the fiber connections

So you could say:

• Die tegnici aktiveer die veselverbindings.
  = The technicians activate the fiber connections.

The exact plural form depends on the noun, but die stays the same.