Если дома есть курага, я добавляю её в йогурт.

Here дома means at home.

It is a very common Russian adverb meaning at home / in the house. So:

• Если дома есть курага... = If there are dried apricots at home...

A learner might expect something like в доме, but дома is the normal everyday way to say at home when talking about where something is.

Examples:

• Я дома. = I’m at home.
• Дома есть молоко. = There is milk at home.

That is a very common question.

Russian usually omits to be in the present tense when linking a subject and a description:

• Я дома. = I am at home.
• Она врач. = She is a doctor.

But есть can still be used in the meaning there is / there are / exists.

So:

• дома есть курага = there are dried apricots at home
• literally: at home there exists dried apricot(s)

Here есть is not just a plain is. It has an existential meaning: is available / is present.

Yes, but курага is often treated as a mass noun in Russian, like a food item in general.

So курага here means something like:

• dried apricots
• some dried apricot
• dried apricot as a food

Russian often uses singular nouns this way for foods and ingredients.

Compare English:

• There’s chicken in the soup.
• There are dried apricots at home.

Russian is comfortable using singular here even when the real-world quantity is more than one.

Because добавляю is imperfective, and it describes a habitual / repeated action.

The sentence means something like:

• If there are dried apricots at home, I add them to yogurt.
• Whenever we have dried apricots at home, I add them to yogurt.

So this is a general habit, not one single future action.

Compare:

• я добавляю = I add / I am adding / I usually add
• я добавлю = I will add once, in the future

If you wanted a one-time future meaning, you could say:

• Если дома будет курага, я добавлю её в йогурт.
• If there are dried apricots at home, I’ll add them to yogurt.

Её refers back to курага.

Since курага is a feminine singular noun, the pronoun is also feminine singular:

• она = she / it
• её = her / it in the accusative or genitive

Here it is the direct object of добавляю, so it means it:

• я добавляю её в йогурт = I add it to yogurt

Russian often uses pronouns this way to avoid repeating the noun:

• Если дома есть курага, я добавляю курагу в йогурт.
• Если дома есть курага, я добавляю её в йогурт.

Both are possible, but the second sounds more natural because it avoids repetition.

Because в + accusative is used here to show movement or putting something into something.

The verb добавлять involves inserting or adding something into a container/mixture, so Russian uses:

• в йогурт = into the yogurt

That is why йогурт is in the accusative case.

Compare:

• добавляю её в йогурт = I add it into the yogurt
• она в йогурте = it is in the yogurt

So:

• в + accusative = direction / result of putting
• в + prepositional = location

Usually в йогурт is the better choice here.

• добавить в йогурт means to add into yogurt
• добавить к йогурту would sound more like add something alongside the yogurt / to go with the yogurt

So if you mean mixing dried apricots into the yogurt itself, в йогурт is the natural phrasing.

In this sentence, it is very close to whenever.

Because both parts are in the present tense and добавляю is imperfective, the whole sentence describes a repeated pattern:

• If/whenever there are dried apricots at home, I add them to yogurt.

So this is not mainly about one specific future situation. It is a general habit.

Yes. The comma is required.

Russian normally uses a comma to separate a subordinate clause introduced by если from the main clause:

• Если дома есть курага, я добавляю её в йогурт.

This is true whether the если clause comes first or second:

• Если дома есть курага, я добавляю её в йогурт.
• Я добавляю её в йогурт, если дома есть курага.

Both need a comma.

Yes. Russian word order is fairly flexible.

The original order is very natural:

• Если дома есть курага, я добавляю её в йогурт.

But you could also say:

• Я добавляю её в йогурт, если дома есть курага.

The meaning stays basically the same. The difference is mainly about emphasis and flow.

Putting the если clause first is very common because it sets up the condition before giving the result.

The main stresses are:

• если́
• до́ма
• курага́
• добавля́ю
• её
• йо́гурт

So one natural pronunciation is:

• Если́ до́ма есть курага́, я добавля́ю её в йо́гурт.

A couple of useful notes:

• её is often written ее in ordinary typing, but it is still pronounced её
• йогурт is stressed on the first syllable: йо́гурт