Комплект сетки уже готов.

Because комплект usually takes the thing included in the set in the genitive case: комплект чего? = a set/kit of what?

So:

• комплект = set, kit
• сетки = of the mesh / of the net / of the screen, depending on context

That makes комплект сетки literally something like a set of mesh/netting or a mesh kit.

Here it is most naturally genitive singular of сетка.

This is a very common point of confusion, because сетки can also be nominative plural. The form is the same, but the grammar tells you which one it is.

In this sentence, after комплект, Russian expects a dependent noun in the genitive, so сетки is understood as of the mesh/net/screen, not nets as the subject.

In Russian, the verb to be is usually omitted in the present tense.

So where English says:

• The kit is ready

Russian normally just says:

• Комплект готов

So Комплект сетки уже готов literally looks like Kit of mesh already ready, but grammatically it means The mesh kit is already ready.

Because готов is the short form adjective, and short-form adjectives are commonly used as the predicate, especially for states like ready, sure, happy, necessary, etc.

Compare:

• готовый комплект = a ready-made / ready kit
  Here the adjective directly modifies the noun.
• комплект готов = the kit is ready
  Here the adjective is the predicate.

So in this sentence, готов is exactly the form you would expect.

Because it agrees with комплект, which is a masculine singular noun.

Short-form готов changes by gender and number:

• готов — masculine
• готова — feminine
• готово — neuter
• готовы — plural

So:

• Комплект готов
• Сетка готова
• Окно готово
• Документы готовы

Уже means already.

It shows that the state has been reached by now:

• Комплект сетки готов = The kit is ready
• Комплект сетки уже готов = The kit is already ready

In other words, the preparation has been completed earlier than expected, or by this point.

Yes, it can change. Russian word order is flexible, and different orders change the emphasis more than the basic meaning.

This version is very natural and neutral:

• Комплект сетки уже готов.

You could also hear:

• Уже готов комплект сетки.
  This can sound a bit more like The mesh kit is already ready with focus on the fact that it is ready now.

• Комплект сетки готов уже.
  This is possible too, often with a slightly more conversational or emphatic feel.

So the meaning stays similar, but the information focus shifts.

Not necessarily. The exact English wording depends a lot on context.

Russian noun + genitive structures can be translated in different ways:

• set of X
• X kit
• X package
• kit for X
• X assembly

So комплект сетки could mean something like:

• mesh kit
• netting kit
• screen kit
• set of mesh components

A learner should not assume that the most literal word-for-word version is always the best English translation.

Normally, no—not in standard neutral Russian for this sentence.

If you want to say The kit is ready, the normal form is:

• Комплект сетки уже готов.

The full form готовый is mainly used before a noun:

• готовый комплект сетки = a ready-made mesh kit

Using готовый at the end here sounds nonstandard or at least much less natural for a basic statement of state.

Russian has no articles, so комплект by itself does not tell you whether English should use a, the, or sometimes no article at all.

The choice comes from context:

• if the speaker means a specific kit already known to both people, English will often use the
• if it is being mentioned for the first time, English may use a

So the Russian sentence does not directly mark that distinction.

A natural stress pattern is:

• компле́кт се́тки уже́ гото́в

Approximate pronunciation:

• kom-PLEKT SYET-ki oo-ZHE go-TOV

The final в in готов is often pronounced more like f at the end of the word in actual speech, so you may hear something close to ga-TOF. That is normal Russian final devoicing.