Όταν στρώνω το κρεβάτι, τινάζω πρώτα το πάπλωμα και μετά συγκεντρώνω τα ρούχα που είναι πάνω στην καρέκλα.

Because this sentence describes a habitual action: something the speaker usually does whenever they make the bed.

In Greek, όταν + present tense is very commonly used for repeated or regular actions:

• Όταν στρώνω το κρεβάτι... = When I make the bed... / Whenever I make the bed...

If the speaker were talking about a single event in the future, Greek would often use a different structure, such as όταν with the subjunctive:

• Όταν στρώσω το κρεβάτι... = When I make the bed / when I’ve made the bed (in the future, one specific time)

So here, στρώνω is present because the sentence is about routine.

It means to make the bed.

Literally, στρώνω can mean things like spread, lay out, or arrange, but in the expression:

• στρώνω το κρεβάτι

it specifically means I make the bed.

This is a set everyday expression, so it’s best to learn it as a whole phrase rather than translating στρώνω word-for-word every time.

Because Greek usually does not need subject pronouns when the verb ending already shows who the subject is.

Here:

• στρώνω = I make
• τινάζω = I shake
• συγκεντρώνω = I gather / collect

The ending -ω tells you the subject is I.

Greek often leaves out pronouns like εγώ unless the speaker wants emphasis or contrast:

• Εγώ στρώνω το κρεβάτι, όχι ο αδερφός μου.
  I make the bed, not my brother.

So in your sentence, leaving out εγώ sounds natural.

Here τινάζω means I shake out.

So:

• τινάζω πρώτα το πάπλωμα
  = I first shake out the duvet/blanket

It often means shaking something to remove dust, straighten it, or fluff it up.

Depending on context, τινάζω can also mean things like:

• shake
• jerk
• dust off

But in this sentence, shake out is the most natural idea.

Πρώτα is an adverb, and here it means first.

In the sentence:

• τινάζω πρώτα το πάπλωμα
  = I first shake out the duvet

It tells us the order of actions.

Then the sentence continues with:

• και μετά = and then / and afterwards

So the sequence is:

1. πρώτα — first
2. μετά — then

Both are adverbs of sequence/time.

Πάπλωμα is a neuter noun, so its article is το in the singular:

• το πάπλωμα = the duvet / quilt

Greek nouns have grammatical gender, and the article has to match the noun:

• masculine: ο
• feminine: η
• neuter: το

Since τινάζω takes a direct object, το πάπλωμα is in the accusative case. For many neuter nouns, the nominative and accusative forms are the same, so you see:

• nominative: το πάπλωμα
• accusative: το πάπλωμα

Because ρούχα is the normal Greek word for clothes, and it is usually used in the plural, just like clothes in English.

So:

• το ρούχο = the garment / item of clothing
• τα ρούχα = the clothes

In everyday Greek, if you mean a group of clothes, you would normally say:

• συγκεντρώνω τα ρούχα = I gather the clothes

Using the singular ρούχο would mean one individual item, not clothes in general.

Here που is a relative pronoun, meaning that, which, or that are depending on how you translate it naturally.

So:

• τα ρούχα που είναι πάνω στην καρέκλα = the clothes that are on the chair

It introduces extra information about τα ρούχα.

A useful thing for learners: Greek που is very common and is much simpler than English relative pronouns in some ways. It doesn’t change form for gender or number here:

• ο άντρας που... = the man who...
• η γυναίκα που... = the woman who...
• το βιβλίο που... = the book that...
• τα ρούχα που... = the clothes that...

Because είναι πάνω στην καρέκλα is a very natural and simple way to say are on the chair.

• είναι = are
• πάνω στην καρέκλα = on the chair

Greek often uses είμαι plus a location, just like English uses to be:

• Το βιβλίο είναι στο τραπέζι. = The book is on the table.

You could also say:

• τα ρούχα που βρίσκονται πάνω στην καρέκλα

But βρίσκονται sounds a bit more formal or more explicitly locational, like are located / are found. In everyday speech, είναι is usually more natural.

Because πάνω here is used with σε to mean on:

• πάνω σε την καρέκλα → contracted to πάνω στην καρέκλα

So:

• σε + την = στην

This is a very common contraction in Greek.

The noun after σε goes in the accusative case, so:

• η καρέκλα = nominative
• την καρέκλα = accusative

That’s why the full form is:

• πάνω στην καρέκλα = on the chair

You may also hear simply:

• στην καρέκλα
• πάνω στην καρέκλα

The version with πάνω is a bit more explicit: up/on top of the chair.

Because it follows the preposition σε (inside the contraction στην), and after σε, the noun normally appears in the accusative.

The noun is feminine:

• nominative: η καρέκλα = the chair
• accusative: την καρέκλα = the chair

Then:

• σε την καρέκλα → στην καρέκλα

So πάνω στην καρέκλα literally contains the accusative form.

The word order is natural, but Greek is more flexible than English.

Original:

• Όταν στρώνω το κρεβάτι, τινάζω πρώτα το πάπλωμα και μετά συγκεντρώνω τα ρούχα που είναι πάνω στην καρέκλα.

This order is clear and idiomatic. But Greek can move things around for emphasis. For example:

• Όταν στρώνω το κρεβάτι, πρώτα τινάζω το πάπλωμα...
• Τα ρούχα που είναι πάνω στην καρέκλα τα συγκεντρώνω μετά.

The meaning stays similar, but the focus shifts.

So the sentence as given is not the only possible order, but it is a very normal one.

Yes, the verbs are in the present tense:

• στρώνω
• τινάζω
• συγκεντρώνω
• είναι

But the meaning here is habitual, not necessarily something happening at this exact moment.

So the sentence means more like:

• When/Whenever I make the bed, I first shake out the duvet and then gather the clothes that are on the chair.

Greek present tense can describe:

• what is happening now
• what usually happens
• general habits

In this sentence, the presence of Όταν and the sequence of routine actions makes the habitual meaning the natural one.