बहन नीचे रसोई में चाय बना रही है।

The basic Hindi word order is usually Subject + other information + Object + Verb.

So here you have:

• बहन = subject
• नीचे रसोई में = location
• चाय = object
• बना रही है = verb phrase

English usually puts the verb earlier: Sister is making tea downstairs in the kitchen.

Hindi usually saves the main verb for the end.

Hindi uses postpositions, not prepositions.

So instead of saying in the kitchen, Hindi says:

• रसोई में
• literally: kitchen in

This is completely normal in Hindi. A few very common postpositions are:

• में = in
• पर = on
• से = from, with, by
• को = to, object marker
• का / की / के = of

नीचे means down, below, or downstairs, depending on context.

In this sentence, it most naturally means something like downstairs or down in the kitchen.

So नीचे रसोई में suggests that the kitchen is downstairs, or that the action is happening down below in the kitchen.

Because बना रही है is the present progressive, which means is making right now.

• बनाती है = makes / usually makes / does make
• बना रही है = is making

So:

• बहन चाय बनाती है = Sister makes tea / Sister usually makes tea
• बहन चाय बना रही है = Sister is making tea

This sentence is describing an action in progress.

Because the subject बहन is feminine singular.

In this kind of sentence, the progressive part agrees with the subject:

• masculine singular: रहा
• feminine singular: रही
• plural / respectful: रहे

So:

• भाई चाय बना रहा है = Brother is making tea
• बहन चाय बना रही है = Sister is making tea
• वे चाय बना रहे हैं = They are making tea

It comes from the verb बनाना, which means to make.

In this pattern, Hindi uses the verb stem plus रहा / रही / रहे:

• बनाना = to make
• बना रहा / रही / रहे = making

So:

• बना रही है = is making

This is just how many -ना verbs behave in the progressive.

This is a very common question.

Hindi usually uses ने with many transitive verbs in the perfective past, but not in the present progressive.

So:

• बहन चाय बना रही है = Sister is making tea
  no ने

But:

• बहन ने चाय बनाई = Sister made tea
  here you do use ने

So the short answer is: no ने is needed because this sentence is not in the perfective past.

In this sentence, the verb agrees with the subject, not the object.

The subject is बहन, which is feminine singular, so you get:

• रही है

Even if the object were something masculine, the verb would still agree with बहन here:

• बहन खाना बना रही है
• बहन पुलाव बना रही है

In non-perfective tenses like the present progressive, agreement is normally with the subject.

Hindi does not have articles like English a / an / the.

So बहन can mean:

• sister
• the sister
• a sister

and चाय can mean:

• tea
• the tea
• some tea

The exact meaning depends on context.

Hindi often leaves out possessives when they are clear from context.

So बहन by itself can mean simply sister, and the listener may understand whose sister is meant from the situation.

If you want to be specific, you can add a possessive:

• मेरी बहन = my sister
• उसकी बहन = his/her sister
• हमारी बहन = our sister

But leaving it out is very natural when the context already makes it clear.

Hindi word order is fairly flexible, but not completely random.

This sentence is natural:

• बहन नीचे रसोई में चाय बना रही है।

You could also hear:

• बहन रसोई में नीचे चाय बना रही है।
• बहन चाय नीचे रसोई में बना रही है।

But the original order is smooth and natural.

Changing the order can shift emphasis. Hindi often moves words around to highlight location, object, contrast, or topic, while still keeping the verb near the end.

A simple learner-friendly pronunciation is:

• बहन = bahan
• नीचे = nee-che
• रसोई = ra-so-ee
• में = mein with nasalization
• चाय = chaay
• बना रही है = ba-naa ra-hee hai

A couple of useful notes:

• च in चाय sounds like ch in chair
• ई is a long ee sound
• में has a nasal quality at the end, not a fully pronounced n

बहन is a general word for sister. It does not by itself specify older or younger.

If you want to be specific, you can say:

• बड़ी बहन = older sister
• छोटी बहन = younger sister

In everyday speech, people also often use family terms like दीदी for an older sister.