Перед тем как заплести косу, сестра сушит волосы феном ещё минуту.

Перед тем как means before or more literally before the moment when.

It is a very common way to introduce an action that happens earlier than the main one:

• Перед тем как уйти, он позвонил. = Before leaving, he called.
• Перед тем как лечь спать, она читает. = Before going to bed, she reads.

In your sentence:

• Перед тем как заплести косу = Before braiding her hair / before making a braid

Russian often uses this full expression where English might just use before + -ing.

Заплести is perfective, and заплетать is imperfective.

Here, the speaker is referring to the braid as a completed action that will happen after the drying is finished:

• заплести косу = to braid the hair into a braid, to finish making the braid

After перед тем как, Russian very often uses a perfective infinitive when the meaning is before doing something completely / before completing an action.

So:

• Перед тем как заплести косу... = Before braiding the hair / before making the braid

If you used заплетать, it would sound more like the process in general, not the completed result.

Because коса is the direct object of заплести.

• dictionary form: коса
• accusative singular: косу

So:

• заплести косу = to braid a braid / to make a braid from the hair

This is a fixed and very common expression.

Also note that коса here means a braid / plait, not a scythe. Russian uses the same word for both, but the context makes it clear.

Here коса means a braid or plait: a hairstyle made by braiding the hair.

So:

• волосы = hair
• коса = braid

The idea is:

1. she dries her hair,
2. then she braids it into a braid.

That is why the sentence has both words:

• сушит волосы = dries her hair
• заплести косу = make a braid

In Russian, волосы is normally used in the plural when talking about someone’s hair in general.

So:

• сушить волосы = to dry one’s hair
• мыть волосы = to wash one’s hair
• расчёсывать волосы = to brush one’s hair

Although English usually treats hair as singular in this meaning, Russian prefers the plural волосы.

Because the instrumental case is often used to show the tool or means used to do something.

• фен = hairdryer
• феном = with a hairdryer

So:

• сушит волосы феном = she dries her hair with a hairdryer

This is a very common use of the instrumental:

• писать ручкой = to write with a pen
• резать ножом = to cut with a knife
• открыть ключом = to open with a key

Because Russian uses the accusative case to express duration of time in many cases.

So:

• минуту = accusative singular of минута

And:

• ещё минуту = for another minute / one more minute

Compare:

• ждать час = to wait for an hour
• спать всю ночь = to sleep all night
• читать минуту = to read for a minute

So here:

• сушит волосы феном ещё минуту = she dries her hair with a hairdryer for another minute

Here ещё means another / one more.

So:

• ещё минуту = for another minute / one more minute

Ещё is a very flexible word in Russian. Depending on context, it can mean:

• still
• yet
• more
• another

In this sentence, the time expression makes the meaning clear: another minute.

Because Russian present tense can describe a habitual or regular action.

So the sentence sounds like a general statement about what she does:

• Перед тем как заплести косу, сестра сушит волосы феном ещё минуту.
• Before braiding her hair, my sister dries it with a hairdryer for another minute.

This does not have to mean she is doing it right now. It can mean this is her routine.

Also, сушить is imperfective, which fits the idea of an ongoing process or repeated habit.

Russian often leaves out possessive words like his, her, or my when the owner is obvious from context.

Here, since the subject is сестра, it is naturally understood that:

• волосы = her hair
• косу = her braid

Russian prefers not to repeat ownership if it is already clear.

English usually needs her, but Russian often does not.

Yes. Russian word order is quite flexible, although the original version is very natural.

Original:

• Перед тем как заплести косу, сестра сушит волосы феном ещё минуту.

Other possible orders include:

• Сестра ещё минуту сушит волосы феном перед тем как заплести косу.
• Перед тем как заплести косу, ещё минуту сестра сушит волосы феном.

The meaning stays basically the same, but the emphasis changes.

The given sentence is a good neutral order:

1. first the before clause,
2. then the main action.

Because Перед тем как заплести косу is a subordinate clause-like introductory part before the main clause.

So Russian separates it with a comma:

• Перед тем как заплести косу, сестра сушит волосы феном ещё минуту.

This is similar to English writing a comma after an introductory phrase:

• Before braiding her hair, my sister dries it with a hairdryer for another minute.

Yes, but the tone changes a little.

• коса = braid, neutral
• косичка = little braid / pigtail / a more affectionate or diminutive form

So:

• заплести косу sounds neutral and standard
• заплести косичку can sound smaller, cuter, or more informal

In many contexts both are possible, but косу is the straightforward neutral choice here.

Russian has no articles, so сестра can mean different things depending on context:

• my sister
• the sister
• sometimes just a sister

In an isolated sentence like this, English would often translate it as my sister if it sounds like a personal statement, but the Russian itself only says sister. The exact English choice depends on the broader context.