Metto la federa pulita sul cuscino prima di dormire.

Because Italian usually drops the subject pronoun when the verb ending already makes the subject clear.

• metto = I put / I am putting
• The ending -o tells you the subject is io

So Metto la federa... is completely normal.
You could say Io metto la federa... only if you want extra emphasis, like I put the pillowcase on, not someone else.

Metto is the 1st person singular present of mettere.

Here it means I put or I put on.

Depending on context, the Italian present tense can mean:

• I put (habit/routine)
• I’m putting (right now)

So this sentence could describe:

• a regular habit before bed, or
• what the speaker is doing at that moment

Federa means pillowcase.

Important distinction:

• cuscino = pillow
• federa = pillowcase

So in the sentence:

• la federa pulita = the clean pillowcase
• sul cuscino = on the pillow

Because pulita has to agree with federa.

• federa is feminine singular
• so the adjective must also be feminine singular
• pulita = clean for a feminine singular noun

Compare:

• il cuscino pulito = the clean pillow
• la federa pulita = the clean pillowcase

In Italian, adjectives often come after the noun, especially when they describe a factual quality.

So:

• la federa pulita = the clean pillowcase

This is the most natural word order here.

Putting the adjective before the noun is sometimes possible in Italian, but it often changes the tone or emphasis. For a simple description, noun + adjective is the normal pattern.

Italian uses the definite article much more often than English does.

So instead of saying:

• my clean pillowcase Italian often just says:
• la federa pulita

And instead of:

• the pillow it says:
• il cuscino

This is common when the object is understood from context or is part of everyday personal routine.

If you wanted to emphasize possession, you could say:

• la mia federa pulita

If you wanted an indefinite sense, you could say:

• una federa pulita = a clean pillowcase

Sul is a contraction of:

• su = on, onto
• il = the

So:

• su + il = sul

Since cuscino is masculine singular, il cuscino becomes sul cuscino after su.

Examples:

• sul tavolo = on the table
• sul letto = on the bed
• sul cuscino = on the pillow

After prima di, Italian uses the infinitive when the subject is the same.

So:

• prima di dormire = before sleeping / before going to sleep

You cannot say:

• prima di dormo

That is ungrammatical.

A useful pattern is:

• prima di + infinitive

Examples:

• prima di mangiare = before eating
• prima di uscire = before going out
• prima di dormire = before sleeping

Yes, absolutely.

• prima di dormire = before sleeping / before going to sleep
• prima di andare a dormire = before going to bed / before going to sleep

The second version is a little longer and more explicit.
The original sentence is perfectly natural and concise.

In context, it can suggest either one, and English translation depends on what sounds most natural.

Literally:

• prima = before
• di dormire = to sleep / sleeping

So it can be understood as:

• before sleeping
• before I sleep
• before going to sleep

In a bedtime routine sentence like this, English often prefers before going to sleep or before bed.

It could be either, because the Italian present tense can express both.

• Metto la federa pulita sul cuscino prima di dormire.
  • could mean I put a clean pillowcase on the pillow before sleeping as a habit
  • or I’m putting the clean pillowcase on the pillow before going to sleep right now

Context tells you which one is meant.

If you wanted to make the habitual meaning clearer, you could add something like:

• di solito = usually
• sempre = always

Yes. Italian word order is flexible, though the original version is very natural.

For example:

• Prima di dormire, metto la federa pulita sul cuscino.

This means the same thing, but it emphasizes the time expression first: Before going to sleep...

The basic structure of the original sentence is:

• Metto = verb
• la federa pulita = direct object
• sul cuscino = place/result
• prima di dormire = time

Yes. A native speaker might also say something like:

• Cambio la federa del cuscino prima di dormire.

That means I change the pillowcase before going to sleep.

Your original sentence is still grammatical and understandable, but cambio la federa may sound more natural if the idea is specifically changing the pillowcase rather than simply putting it on.