Πριν κοιμηθώ, έβαλα λίγη λοσιόν στα χέρια, άλλαξα την παπλωματοθήκη και άφησα το νεσεσέρ κάτω από το κρεβάτι.

Because after πριν when Greek means before doing something, it normally uses the subjunctive, not a past indicative form.

• κοιμηθώ = I go to sleep / I fall asleep in the aorist subjunctive
• So Πριν κοιμηθώ literally means before I sleep / before I go to sleep, but in natural English it is before I went to sleep or before going to sleep, depending on context.

A past indicative like κοιμήθηκα means I went to sleep as a finished fact, which does not fit after πριν here.

κοιμηθώ is the 1st person singular aorist subjunctive of κοιμάμαι (to sleep / to go to sleep).

Important idea:

• κοιμάμαι often refers to the state of sleeping
• κοιμηθώ often points to the event of falling asleep / going to sleep

So in Πριν κοιμηθώ, the focus is on the moment of going to sleep, not the whole state of being asleep.

They are all in the aorist past, because the sentence lists completed actions in sequence:

• έβαλα = I put / applied
• άλλαξα = I changed
• άφησα = I left

The aorist is very common when narrating a series of simple finished actions. It is similar to English I did X, did Y, and did Z.

λίγη means a little / some and agrees with λοσιόν.

So:

• λίγη λοσιόν = a little lotion / some lotion

Greek often uses a word like λίγος, λίγη, λίγο where English might simply say some.

Here:

• λίγη = feminine singular accusative
• λοσιόν is treated as a feminine noun

So the phrase means I put a little lotion on my hands.

λοσιόν is a loanword (from French, ultimately used internationally), and in Modern Greek it is usually treated as feminine.

That is why you see:

• λίγη λοσιόν
• often also η λοσιόν

Many loanwords in Greek are indeclinable or only partly adapted, so the noun itself may not visibly change much across cases, while the article or adjective shows the grammar.

Because στα is the contracted form of σε + τα.

So:

• σε τα χέρια → στα χέρια

This is completely normal and standard.

Here:

• σε = in/on/to
• τα χέρια = the hands

So στα χέρια means on the hands or to the hands, depending on context. With lotion, English naturally says on my hands.

Greek very often uses the definite article with body parts where English prefers a possessive.

So Greek may say:

• στα χέρια = literally on the hands

But from context, it naturally means:

• on my hands

This is very common in Greek. The possessor is often understood from the subject of the sentence.

Yes, it is a compound noun. It breaks down like this:

• πάπλωμα = duvet / quilt
• θήκη = case / cover

So:

• παπλωματοθήκη = duvet cover

In the sentence:

• την παπλωματοθήκη = the duvet cover in the accusative, because it is the direct object of άλλαξα (I changed).

It means I changed the duvet cover, and in natural usage that usually implies I replaced it / put on a fresh one.

Greek αλλάζω works much like English change in this kind of household context:

• αλλάζω την παπλωματοθήκη
• αλλάζω τα σεντόνια
• αλλάζω ρούχα

So it does not just mean mentally modifying something; it often means swap out / replace.

νεσεσέρ means a toiletry bag, wash bag, or sometimes a small cosmetics case.

In this sentence it appears as:

• το νεσεσέρ

So it is treated here as neuter.

Like several borrowed words in Greek, νεσεσέρ is commonly used with an article that shows its gender, while the noun itself does not change much.

After από, Greek uses the accusative.

So:

• το κρεβάτι is accusative here

The phrase:

• κάτω από το κρεβάτι = under the bed

This is a fixed and very common expression:

• πάνω από = above
• κάτω από = below / under
• μέσα σε = inside
• έξω από = outside

Not completely. Greek word order is fairly flexible, though some versions sound more natural than others.

This sentence is very natural:

• Πριν κοιμηθώ, έβαλα λίγη λοσιόν στα χέρια, άλλαξα την παπλωματοθήκη και άφησα το νεσεσέρ κάτω από το κρεβάτι.

But Greek could move parts around for emphasis, for example:

• Πριν κοιμηθώ, άφησα το νεσεσέρ κάτω από το κρεβάτι...
• Λίγη λοσιόν έβαλα στα χέρια πριν κοιμηθώ... (more marked)

The given order is a neutral narrative order: time phrase first, then a sequence of actions.

Because Πριν κοιμηθώ is an introductory subordinate time clause: Before I went to sleep / Before going to sleep.

In standard written Greek, it is normal to separate that opening clause with a comma before the main clause:

• Πριν κοιμηθώ, ...

This is similar to English:

• Before I went to sleep, ...

Not naturally in this context.

The sentence describes a set of single completed actions:

• put on lotion
• changed the duvet cover
• left the toiletry bag under the bed

That is exactly what the aorist is for.

The imperfect would suggest repeated, ongoing, habitual, or background actions, which does not fit as well here. For example:

• έβαζα = I was putting / I used to put
• άλλαζα = I was changing / I used to change
• άφηνα = I was leaving / I used to leave

So the aorist is the natural choice.