В этом хостеле я чувствую себя как дома.

Because в этом хостеле means in this hostel as a location, so Russian uses the prepositional case after в for location.

• этот хостел = this hostel (dictionary/basic form)
• в этом хостеле = in this hostel

Compare:

• Я живу в этом хостеле. = I live in this hostel.
• Я иду в этот хостел. = I am going into this hostel.

So:

• location → в + prepositional
• motion toward → в + accusative

Because adjectives and demonstratives in Russian must agree with the noun in gender, number, and case.

Here:

• хостел is masculine singular
• after в with location, it must be in the prepositional case
• so этот becomes этом

Mini-paradigm:

• nominative: этот хостел
• accusative: в этот хостел (into this hostel)
• prepositional: в этом хостеле (in this hostel)

So этом is simply the correct prepositional form of этот.

For the same reason: the noun must also go into the prepositional case after в when it means location.

• basic form: хостел
• prepositional singular: хостеле

So:

• хостел = hostel
• в хостеле = in a hostel
• в этом хостеле = in this hostel

This -е ending is very common for masculine nouns in the prepositional singular.

In Russian, чувствовать себя is the normal way to say to feel in the sense of to feel oneself / to be feeling.

So:

• Я чувствую себя хорошо. = I feel good.
• Он чувствует себя плохо. = He feels bad.

The word себя is the reflexive pronoun, meaning something like oneself.

This is different from чувствовать when it means to feel/sense something:

• Я чувствую холод. = I feel cold.
• Я чувствую запах дыма. = I smell / feel the smell of smoke.

But for talking about your state or condition, Russian usually uses чувствовать себя.

Here себя functions as the object of чувствую, so it is effectively in the accusative role.

A small complication: the form себя is used for both genitive and accusative, so the form itself does not change between those two cases.

For practical learning, the important point is:

• чувствовать себя is a fixed, very common pattern
• you can learn it as a whole expression meaning to feel

Как дома is a very common fixed expression meaning like at home or as if at home.

Here дома does not mean the plural noun houses. In this expression, дома means at home.

So:

• дома = at home
• как дома = like at home

Examples:

• Чувствуйте себя как дома. = Make yourself at home.
• У них я всегда как дома. = At their place I always feel at home.

So in your sentence, как дома means the speaker feels comfortable, relaxed, familiar, and welcome.

It looks the same, but here it is functioning as an adverb, meaning at home.

Compare:

• дома большие = the houses are big
  Here дома is a noun form related to дом.

• Я дома. = I am at home.
  Here дома is an adverb.

In как дома, it is definitely the adverbial meaning: like at home.

Yes. Russian word order is flexible, and changing it usually changes emphasis, not the core meaning.

Original:

• В этом хостеле я чувствую себя как дома.

This sounds natural and sets the scene first: In this hostel...

Other possible orders:

• Я чувствую себя как дома в этом хостеле.
  More neutral if you want to start with I.

• Как дома я чувствую себя в этом хостеле.
  More marked/literary; emphasis on like at home.

So the original sentence is very natural, but it is not the only possible order.

Yes, я can sometimes be omitted in Russian if the meaning is obvious from the verb ending.

• Чувствую себя как дома. = I feel at home.

Because чувствую already shows first person singular, the subject is recoverable.

But Russian often keeps pronouns for clarity, contrast, or natural rhythm. In this sentence, я sounds completely normal.

Compare:

• В этом хостеле чувствую себя как дома. = possible, a bit more conversational
• В этом хостеле я чувствую себя как дома. = clear and natural

Yes. Чувствовать is the imperfective verb, and it is the normal choice for describing an ongoing state or general feeling.

Here the speaker is describing how they feel in this place, not a single completed event.

• чувствовать = to feel
• почувствовать = to start feeling / to feel suddenly / to perceive at a moment

Compare:

• В этом хостеле я чувствую себя как дома.
  = I feel at home in this hostel.
  Ongoing/general state.

• Сразу я почувствовал себя как дома.
  = I immediately felt at home.
  A change or moment of realization.

So чувствую is exactly right here.

Yes, but the meaning changes slightly because the noun changes.

• хостел = hostel
• гостиница = hotel
• общежитие = dormitory / hostel in the student-residence sense

So:

• В этом хостеле я чувствую себя как дома. = In this hostel I feel at home.
• В этой гостинице я чувствую себя как дома. = In this hotel I feel at home.

Notice the grammar changes too:

• хостел is masculine → в этом хостеле
• гостиница is feminine → в этой гостинице

A careful pronunciation would be roughly:

V É-təm hos-TÉ-lʲe ya CHÚ-stvuyu si-BYÁ kak do-MÁ.

Main stresses:

• в э́том
• хосте́ле
• чу́вствую
• себя́
• дома́

A couple of helpful notes:

• что/чувствую type clusters can sound hard for learners; чувствую is often pronounced more smoothly than it looks.
• себя has stress on the last syllable: се-БЯ
• дома meaning at home is stressed до-МА

Usually yes. It normally suggests comfort, ease, and familiarity.

If someone says:

• Я чувствую себя как дома.

they usually mean:

• I feel comfortable
• I feel welcome
• the place feels familiar and easy

It can occasionally be used humorously or ironically depending on context, but by default it is positive.

Yes, very much. You can reuse the pattern:

В + place (prepositional), я чувствую себя как дома.

Examples:

• У вас я чувствую себя как дома. = I feel at home at your place.
• В этой семье он чувствует себя как дома. = He feels at home in this family.
• На работе я не чувствую себя как дома. = I don’t feel at home at work.

A very useful related phrase is:

• Чувствуйте себя как дома. = Make yourself at home.

So this sentence is not just one sentence to memorize; it is a very productive model.