Jeg hænger min frakke bag døren i entreen.

Because in Danish, a possessive like min, din, hans, hendes, etc. normally replaces the separate definite marking.

So:

• en frakke = a coat
• frakken = the coat
• min frakke = my coat

You do not usually say min frakken in standard Danish. That would be like saying my the coat.

Because døren is the definite form: the door.

In Danish, definiteness is often added to the end of the noun:

• en dør = a door
• døren = the door

So bag døren means behind the door, not just behind a door.

Danish usually puts the definite article at the end of the noun instead of using a separate word before it.

Examples:

• en frakke = a coat
• frakken = the coat
• en dør = a door
• døren = the door

So:

• døren literally works like door-the
• entreen works like hallway-the or entrance hall-the

This is one of the biggest structural differences from English.

Hænger is present tense.

In Danish, the present tense often covers both:

• I hang
• I am hanging

So Jeg hænger min frakke bag døren i entreen can mean either a general action or something happening now, depending on context.

If Danish wants to stress that something is happening right now, it can use a structure like er ved at:

• Jeg er ved at hænge min frakke bag døren i entreen = I am in the process of hanging my coat behind the door in the hallway

But the simple present hænger is very common.

Because hænger is the finite present-tense form, which is what a normal statement needs.

Compare:

• at hænge = to hang
• jeg hænger = I hang / I am hanging

So after the subject jeg, you need the present-tense form hænger.

Bag means behind.

So:

• bag døren = behind the door

It introduces a location. In this sentence, it tells you where the coat is being hung.

The location phrase is:

• bag døren i entreen

This means the coat is being hung behind the door, and that door is in the hallway/entrance area.

I means in, and entreen is the definite form of entre: the hallway / the entrance hall.

So:

• i entreen = in the hallway / in the entrance hall

The noun is definite because the speaker has a specific hallway in mind, usually the hallway of the home.

The basic form is entre or sometimes entré in Danish spelling.

It is a common-gender noun, so its forms are:

• en entre / en entré = a hallway / an entrance hall
• entreen / entréen = the hallway / the entrance hall

In your sentence, entreen is the definite singular form.

The basic order is:

• Jeg = subject
• hænger = verb
• min frakke = direct object
• bag døren i entreen = place/location

So the pattern is:

subject + verb + object + location

That is a very normal Danish sentence pattern.

You can move the location to the front for emphasis, but then the verb still stays in second position:

• I entreen hænger jeg min frakke bag døren.

That verb-second pattern is very important in Danish.

In normal understanding, i entreen gives the larger setting for the whole action, and especially for døren:

• the coat is hung behind the door
• that door is in the hallway

So the most natural reading is: behind the door in the hallway.

Danish often stacks location phrases like this without needing extra words.

A rough guide is:

• hænger ≈ HENG-er, but with the Danish æ sound, which is more open than English e

A few pronunciation points:

• æ is like the vowel in cat, but not exactly the same
• the g in hænger is softer than an English hard g
• the ending -er in Danish is often pronounced very lightly

So do not pronounce it like fully English hanger. The Danish sound is softer and flatter.

Usually yes in this kind of sentence.

Frakke normally means coat, especially an outer coat. It is not usually the same as jacket in every context.

So:

• frakke = coat
• jakke = jacket

In this sentence, min frakke clearly means my coat, the thing you would hang up when coming inside.