Сегодня она сделала ровный пробор, заплела косу и сказала, что так ей удобнее работать.

Because Russian past-tense verbs agree with the subject in gender and number.

The subject here is она, so the verbs are feminine singular:

• сделала
• заплела
• сказала

Compare:

• он сделал — he did/made
• она сделала — she did/made
• они сделали — they did/made

So the -ла ending is a very common sign of a feminine singular past-tense verb.

They are perfective because the sentence describes completed actions:

• she made a parting
• she braided her hair
• she said something

Perfective verbs are very common when Russian tells a sequence of finished events.

Here:

• сделала = completed the action of making the parting
• заплела = completed the action of braiding
• сказала = completed the action of saying

If you used imperfective forms such as делала or заплетала, the focus would shift more toward the process, repetition, or background activity, not the finished result.

Пробор is the parting in someone’s hair — the line where the hair is divided.

So сделала пробор literally means made a parting, which corresponds to English parted her hair or made a part in her hair.

This is a normal Russian way to say it.

Here ровный means something like:

• straight
• even
• neat

So ровный пробор is a straight/neat parting.

In hair-related contexts, ровный often suggests that the line is clean and tidy, not messy or uneven.

This is about the accusative case, which is used for direct objects.

Both пробор and коса are direct objects here:

• сделала ровный пробор
• заплела косу

But they behave differently because of their gender and type:

1. Masculine inanimate nouns

For masculine inanimate nouns, the accusative usually looks the same as the nominative:

• nominative: ровный пробор
• accusative: ровный пробор

So there is no visible change.

2. Feminine nouns in -а

For many feminine nouns, the accusative changes -а to -у:

• nominative: коса
• accusative: косу

So заплела косу means braided a braid/plait.

Yes, here коса means braid or plait.

Russian коса can have more than one meaning, including:

• braid/plait
• scythe
• sometimes sandspit in geography

But in this sentence, because of the hair context (пробор, работать with hair arranged conveniently), it clearly means a braid.

So заплела косу = braided her hair into a braid.

Because the subject is already clear.

Russian often avoids repeating the subject when several actions are done by the same person:

• Сегодня она сделала ровный пробор, заплела косу и сказала...

This is very natural. English often does the same:

• Today she made a straight parting, braided her hair, and said...

Repeating она before every verb would usually sound unnecessary unless you wanted special emphasis.

They are there for two different reasons.

Comma after пробор

This separates items in a series of actions:

• сделала ровный пробор
• заплела косу
• и сказала

So the sentence lists what she did.

Comma before что

This introduces a subordinate clause:

• сказала, что... = said that...

Russian normally puts a comma before что in this structure.

Here так means this way or like this.

It refers back to the hairstyle she just made:

• with her hair parted like this
• with her hair braided like this
• in this arrangement

So the idea is:

• she said that it is more convenient for her to work this way

Because Russian uses a different structure here.

ей удобнее работать

Literally, this is close to:

• to her, it is more convenient to work
• it is more convenient for her to work

This is a very common Russian pattern:

• мне трудно понять — it is hard for me to understand
• ему легче читать — it is easier for him to read
• ей удобно сидеть — it is comfortable for her to sit

The person experiencing the feeling or condition is often put in the dative case:

• ей = to/for her

And the action itself appears as an infinitive:

• работать = to work

So ей удобнее работать is the normal way to say it’s more convenient for her to work.

By contrast, она удобнее работает would mean something more like she works more conveniently, which is not the intended idea.

Удобнее is the comparative form, meaning more convenient.

So the sentence implies a comparison, even if the other option is not stated directly. The unstated meaning is something like:

• more convenient than wearing her hair differently
• more convenient than leaving it loose
• more convenient than before

If the sentence used удобно, it would simply mean:

• it is convenient for her to work this way

But удобнее adds the idea of comparison: this way is better/more convenient.

Yes, ей так удобнее работать is also possible.

Russian word order is flexible, and changing the order often changes emphasis, not the basic meaning.

так ей удобнее работать

This puts a little more focus on так — this way

ей так удобнее работать

This sounds slightly more neutral and straightforward

In both cases, the meaning is essentially:

• it’s more convenient for her to work this way

So the original word order is natural; it just highlights this way a bit more.