Сьогодні ввечері я не буду вдома.

Буду is the 1st person singular future form of бути (to be).

So:

• я буду = I will be
• я не буду = I will not be

In this sentence, Ukrainian is expressing a future state: at some time later today, I will not be at home.

This is very natural in Ukrainian. English often sounds a bit less explicit because I won’t be home tonight is already idiomatic, but grammatically the Ukrainian sentence is doing exactly what you would expect: future of to be + not + location.

In Ukrainian, не normally goes directly before the verb it negates.

So:

• буду = I will be
• не буду = I will not be

That is the standard position.
So я не буду вдома literally works as I not will-be at home, which corresponds to natural English I will not be home.

Вдома means at home or home in the sense of being where you live.

It does not usually mean literally inside the building/house. For that more literal meaning, Ukrainian would more likely use something like в домі or у будинку, depending on context.

So:

• вдома = at home / home
• в домі = in the house
• у будинку = in the building / in the house

This is an important distinction for English speakers, because English home is not quite the same as house, and Ukrainian makes that distinction too.

For practical learning purposes, it is best to treat вдома as a fixed adverb meaning at home.

Even though historically it comes from older forms related to в + дім/home, in modern Ukrainian learners usually just remember it as a single unit:

• Я вдома = I’m at home
• Я буду вдома = I’ll be at home
• Я не буду вдома = I won’t be at home

So yes, the most useful approach is: memorize вдома as a whole.

Сьогодні ввечері means this evening or tonight.

The two parts are:

• сьогодні = today
• ввечері = in the evening / this evening

Together they narrow the time down to this evening, often naturally translated as tonight.

A very literal breakdown would be:

• сьогодні ввечері = today in the evening

But in normal English you would usually say this evening or tonight.

Yes, ввечері and увечері are both possible.

This is part of a very common Ukrainian pattern where в / у alternate for smoother pronunciation. The choice often depends on the surrounding sounds and on what sounds more natural in speech.

So you may see:

• сьогодні ввечері
• сьогодні увечері

Both mean the same thing.

In your sentence, сьогодні ввечері is completely normal and natural.

Yes, very often.

Because the verb form буду already tells you the subject is I, Ukrainian can drop я if it is clear from context.

So both are possible:

• Сьогодні ввечері я не буду вдома.
• Сьогодні ввечері не буду вдома.

The version with я is still perfectly natural. Including it can make the sentence a bit clearer, a bit more explicit, or slightly more contrastive depending on context.

The word order is flexible.

Your sentence:

• Сьогодні ввечері я не буду вдома.

is very natural, especially if you want to foreground the time: this evening.

Other natural orders include:

• Я сьогодні ввечері не буду вдома.
• Я не буду вдома сьогодні ввечері.

The core meaning stays the same, but the focus shifts slightly:

• putting сьогодні ввечері first emphasizes when
• putting я first emphasizes who
• putting вдома later keeps the location as the final important point

So the original sentence is not the only possible one, but it is a very normal choice.

Yes, a Ukrainian speaker would absolutely say this. It is natural and correct.

Depending on situation, there are also shorter or more conversational alternatives, for example:

• Сьогодні ввечері мене не буде вдома.

This literally means something like There won’t be me at home this evening, but in natural English it is still I won’t be home tonight.

That version is also very common.
So both are natural:

• Я не буду вдома
• Мене не буде вдома

The version with я не буду is straightforward and very learner-friendly.

Good comparison:

Present

• Я не вдома. = I’m not at home.

Ukrainian often does not use a present-tense form of to be in sentences like this.

Future

• Я не буду вдома. = I won’t be at home.

Here the future of бути is needed.

Past

• Я не був вдома. = I wasn’t at home.
• Я не була вдома. = I wasn’t at home. if the speaker is female

So the sentence you were given uses the normal future pattern.

No. Буду does not show gender.

In the future tense:

• я буду = I will be

This is the same whether the speaker is male or female.

Gender matters in the past tense, not here:

• я був = I was if male
• я була = I was if female

So in your sentence, nothing changes for gender.

In normal speech, learners do not need to over-pronounce it as two completely separate English-style v sounds.

The spelling ввечері reflects the prefix-like в plus the word beginning with вечір-, but in natural pronunciation it flows smoothly as one word.

The main thing is:

• do not split it awkwardly
• keep the stress on -ве- in вве́чері

A learner-friendly approximation is:

• вве́чері ≈ VVE-che-ri

But spoken naturally, it will sound smoother than that spelling-based breakdown suggests.