Я долго училась пеленать малыша аккуратно, чтобы ему было тепло и удобно.

Because the speaker is understood to be female.

In the past tense, Russian verbs change for gender:

• учился = he learned / was learning
• училась = she learned / was learning
• училось = it learned / was learning
• учились = they learned / were learning

So Я долго училась... means I (female) spent a long time learning...

Also, the -сь shows that this is the verb учиться.

Here учиться + infinitive means to learn to do something.

So:

• учиться пеленать = to learn to swaddle

This is a very common pattern in Russian:

• учиться готовить = to learn to cook
• учиться водить = to learn to drive
• учиться говорить по-русски = to learn to speak Russian

So the structure is:

• Я училась пеленать малыша
  = I was learning to swaddle the baby

Долго means for a long time.

It tells you how long the learning process lasted:

• Я долго училась... = I spent a long time learning...

It does not mean slowly here.
For slowly, Russian would use медленно.

So:

• долго = for a long time
• медленно = slowly

The verb is imperfective because the sentence focuses on the process of learning, not on completing it in one moment.

• училась suggests: I was learning / I spent time learning
• It emphasizes duration and effort

This fits well with долго.

If you used a perfective verb, the meaning would shift toward successfully learning/mastering something, rather than the ongoing process.

So in this sentence, училась is natural because the speaker is talking about the time it took to acquire the skill.

Пеленать means to swaddle a baby, that is, to wrap a baby in cloth or a blanket in a snug way.

It is a specific childcare verb, not just a general word for wrap.

Aspect-wise, пеленать is imperfective.
A common perfective partner is запеленать.

• пеленать = to be swaddling / to swaddle in general
• запеленать = to swaddle up, to complete the swaddling

In this sentence, the imperfective is natural because it refers to learning the skill in general.

Because малыша is the accusative singular form, and it is the direct object of пеленать.

The noun is:

• nominative: малыш = little child / baby
• accusative: малыша

This happens because малыш is:

• masculine
• animate

For masculine animate nouns, the accusative usually looks like the genitive:

• Я вижу малыша = I see the baby
• Я пеленаю малыша = I swaddle the baby

So малыша is exactly what we expect here.

Малыш literally means something like little one, little child, or baby. It often sounds more affectionate or intimate than ребёнок.

Compare:

• ребёнок = child (neutral, general)
• малыш = little child / baby / little one (warmer, more affectionate)
• младенец = infant (more formal or medical)

So малыша here sounds natural in a caring, family context.

Аккуратно is an adverb meaning carefully, neatly, or tidily, depending on context.

Here it modifies пеленать:

• пеленать аккуратно = to swaddle carefully / neatly

So the idea is not just learning to swaddle the baby, but learning to do it properly and carefully.

Russian adverbs often end in -о:

• быстро = quickly
• медленно = slowly
• аккуратно = carefully / neatly

Russian word order is fairly flexible, and adverbs can often move around more than in English.

Here:

• пеленать малыша аккуратно

sounds natural and means to swaddle the baby carefully

You could also hear:

• аккуратно пеленать малыша

The meaning stays basically the same, but the emphasis shifts a little.

In this sentence, the chosen order sounds smooth and neutral.

Чтобы means so that, in order that, or sometimes so.

It introduces a purpose clause:

• ...чтобы ему было тепло и удобно
• ...so that he would be warm and comfortable

So the sentence explains why the speaker was learning to swaddle the baby carefully:
the goal was the baby’s comfort.

This is one of the most common uses of чтобы in Russian.

Ему is the dative form of он (he / him).

Here Russian uses a structure that literally works like:

• to him it was warm and comfortable

So:

• ему было тепло и удобно
• literally: it was warm and comfortable for him
• natural English: he was warm and comfortable

This is very common in Russian. The person experiencing a state often goes in the dative:

• мне холодно = I am cold
• ей грустно = she is sad
• ему удобно = he is comfortable

Good question. After чтобы, Russian very often uses a past-tense form to express a desired or intended result, even when English might use would be or just the base idea.

So:

• чтобы ему было тепло и удобно

means:

• so that he would be warm and comfortable
• so that he was warm and comfortable in a natural English translation depending on context

The form было is neuter singular because this is an impersonal construction.

So although it looks like plain past tense, after чтобы it often functions more like a subordinated result or purpose form.

Because here Russian is describing a state, not directly describing a noun.

• ему было тепло и удобно = he was warm and comfortable
• literally: it was warm and comfortable for him

So тепло and удобно are not regular adjective forms here. They function as predicative words describing how someone feels.

Compare:

• тёплое одеяло = a warm blanket
• удобная кровать = a comfortable bed

But:

• ему тепло = he is warm
• ему удобно = he is comfortable

So the sentence is about the baby’s condition, not about describing an object.

Because было does not agree with тепло and удобно the way a normal adjective agrees with a noun.

This is an impersonal construction, and было appears in the default neuter singular form.

That is normal in sentences like:

• Было холодно. = It was cold.
• Мне было грустно. = I was sad.
• Ему было тепло и удобно. = He was warm and comfortable.

So the neuter singular было is standard here.

Not naturally. Russian and English organize this idea differently.

A more natural English rendering would be:

• I spent a long time learning to swaddle the baby carefully, so that he would be warm and comfortable.

The key point is that:

• Я долго училась... = I spent a long time learning...
• not I long learned...

So you should understand долго idiomatically as expressing duration.

Yes, it is very natural.

The sentence flows like this:

• Я долго училась — main action
• пеленать малыша аккуратно — what skill was being learned
• чтобы ему было тепло и удобно — the purpose

Russian word order is flexible, but this version sounds smooth and neutral.

You could rearrange parts for emphasis, but the original is a very good standard sentence for a learner to study.