Після обіду я починаю працювати.

Because після requires the genitive case.

• Dictionary form: обід = lunch
• After після: обіду = after lunch

So:

• після обіду = after lunch

This is a very common pattern in Ukrainian:

• після уроку = after the lesson
• після роботи = after work
• після дощу = after the rain

Після means after.

It is a preposition that normally takes the genitive case. That is why the noun after it changes form.

Examples:

• після обіду = after lunch
• після школи = after school
• після зустрічі = after the meeting

So if you see після, you should usually expect the next noun to be in the genitive.

Yes, you often can leave it out.

Ukrainian verbs usually show the subject clearly, so починаю already tells us the subject is I.

• Я починаю працювати. = I start working.
• Починаю працювати. = (I) start working.

Including я can make the sentence clearer, more explicit, or slightly more emphatic. In a neutral sentence, either version works.

It means both start to work and start working.

In Ukrainian, after починати / почати (to begin / to start), you commonly use an infinitive:

• починаю працювати = I begin to work / I start working
• починаю читати = I begin to read
• починаю вчити українську = I begin studying Ukrainian

English can use either to work or working, but Ukrainian normally uses the infinitive form.

Працювати is the infinitive: to work.

It is also an imperfective verb, which means it describes an ongoing process, repeated activity, or general action rather than a completed result.

In this sentence:

• починаю працювати = I start working

You do not need any word like English to before it. The infinitive itself is enough.

Because the sentence describes a habit or regular routine.

• починаю = I begin / I start

So the full sentence means something like:

• After lunch, I start working
• After lunch, I begin work
• After lunch, I usually start working

If you wanted a single future event, Ukrainian would more naturally use the perfective future:

• Після обіду я почну працювати. = After lunch I will start working.

So:

• починаю = habitual / regular / general present
• почну = one future starting point

They come from two related verbs:

• починати → починаю = imperfective, present
• почати → почну = perfective, future

In practice:

• Після обіду я починаю працювати.
  = After lunch I start working.
  This sounds like a routine or usual schedule.

• Після обіду я почну працювати.
  = After lunch I will start working.
  This refers more naturally to one specific future occasion.

This imperfective/perfective contrast is very important in Ukrainian.

Yes. Ukrainian word order is fairly flexible.

The sentence:

• Після обіду я починаю працювати.

is a neutral, natural way to say it. But you can also say:

• Я починаю працювати після обіду.
• Працювати я починаю після обіду.

These versions all mean basically the same thing, but the focus changes slightly.

For example:

• Після обіду я починаю працювати.
  Focuses first on the time: after lunch

• Я починаю працювати після обіду.
  Starts with I, which can sound a bit more personal or contrastive

For learners, the original order is a good neutral model.

Usually, yes.

In standard modern Ukrainian, обід most commonly means lunch, the midday meal.

So:

• після обіду = after lunch

In some contexts, meal words can vary a bit by region or family usage, but for a learner, lunch is the best default meaning here.

A rough pronunciation guide is:

Pislia obídu ya pochynáyu pratsyuváty.

A few useful notes:

• після sounds roughly like PIS-lya
• обіду has stress on -бі-: o-BEE-du
• починаю has stress on -на-: po-chy-NA-yu
• працювати has stress on -ва-: prats-yu-VA-ty

This is only an approximation, but it can help you get started.

Not exactly.

Починаю працювати means I start working, not I go to work.

Compare:

• Після обіду я починаю працювати. = After lunch I start working.
• Після обіду я йду на роботу. = After lunch I go to work.

The first focuses on the beginning of the activity.
The second focuses on going to the workplace.

So even if the meaning may be similar in some real-life situations, the Ukrainian wording is different.