Not kâğıdını ekrana yapıştırdım, çünkü dosya ekini göndermeyi unutmak istemiyorum.

Because not kâğıdını is the definite direct object of yapıştırdım.

The base form is not kâğıdı = note paper / note sheet.
When that noun phrase is a specific object, Turkish usually adds the accusative ending:

• not kâğıdı = a note paper / note sheet
• not kâğıdını = the note paper / the note sheet

So in this sentence, the speaker is talking about a specific note they stuck on the screen.

Also, not kâğıdı is a noun compound, so the ending attaches to the second word.

This is due to consonant softening.

The dictionary form is kâğıt. When a vowel-initial ending is added, the final t often softens to d:

• kâğıt → kâğıdı
• kanat → kanadı
• ağaç → ağacı

So:

• not kâğıdı = note paper
• not kâğıdını = the note paper, as a definite object

This is a very common sound change in Turkish.

It is the combination of the noun-compound ending already present in kâğıdı plus the accusative.

A useful way to think about it:

• not kâğıdı already ends in a compound marker
• when you add the accusative, Turkish inserts -n-
• so you get not kâğıdını

The same thing happens in:

• dosya eki → dosya ekini
• araba kapısı → araba kapısını

So that -n- is not random; it appears very often with this kind of noun phrase.

Because ekran-a is the dative case, and with yapıştırmak Turkish often uses the pattern:

bir şeyi bir yere yapıştırmak = to stick something onto somewhere

So:

• not kâğıdını = the note
• ekrana = onto the screen
• yapıştırdım = I stuck / attached

This is very natural Turkish:

• Duvara astım = I hung it on the wall
• Buzdolabına yapıştırdım = I stuck it on the fridge

They are related, but not the same.

• yapışmak = to stick, to become stuck
• yapıştırmak = to stick something, to attach something

So:

• Not ekrana yapıştı = The note stuck to the screen
• Notu ekrana yapıştırdım = I stuck the note to the screen

In your sentence, the speaker is doing the action to an object, so yapıştırmak is the correct verb.

Çünkü means because.

It connects the first clause with the reason:

• Not kâğıdını ekrana yapıştırdım = I stuck the note to the screen
• çünkü... = because...
• dosya ekini göndermeyi unutmak istemiyorum = I don’t want to forget to send the file attachment

So the structure is very similar to English: I stuck the note to the screen, because I don’t want to forget...

Turkish also has other ways to say because, such as -dığı için, but çünkü is simple and very common.

For the same reason as not kâğıdını: it is a definite object inside the expression göndermeyi unutmak.

The base noun compound is:

• dosya eki = file attachment

With the accusative:

• dosya ekini = the file attachment

So the sentence is not talking about attachments in general, but about a specific attachment the speaker needs to send.

Because unutmak usually takes a verbal noun in -mA form, often with the accusative.

So Turkish says:

• gitmeyi unuttum = I forgot to go
• aramayı unuttum = I forgot to call
• göndermeyi unuttum = I forgot to send

Here:

• göndermek = to send
• gönderme = sending / the act of sending
• göndermeyi = the sending, as the object of unutmak

So göndermeyi unutmak literally looks more like to forget the sending, but in natural English it means to forget to send.

Turkish often builds long verb chains by turning earlier verbs into noun-like forms and putting the final finite verb at the end.

Here is the chain:

• göndermek = to send
• göndermeyi unutmak = to forget to send
• göndermeyi unutmak istemiyorum = I do not want to forget to send

So the logic is:

1. send
2. forget to send
3. not want to forget to send

The last verb, istemiyorum, carries the person and tense information:

• -yor = present/progressive
• -um = I

In everyday Turkish, istiyorum / istemiyorum is the normal way to say I want / I don’t want.

So:

• istemiyorum = I don’t want

By contrast, istemem can sound more like:

• I wouldn’t want
• I don’t want it, as a firmer statement
• a more general or stylistically different form

In this sentence, unutmak istemiyorum is the most natural everyday way to say I don’t want to forget.

No. Turkish word order is flexible, although the version in the sentence is perfectly natural.

This sentence starts with the object:

• Not kâğıdını ekrana yapıştırdım...

That puts early attention on the note.

You could also say something like:

• Dosya ekini göndermeyi unutmak istemiyorum, bu yüzden not kâğıdını ekrana yapıştırdım.
• Dosya ekini göndermeyi unutmak istemediğim için not kâğıdını ekrana yapıştırdım.

All of these are grammatical, but they shift the emphasis a little. Turkish often moves things around for focus, topic, or style.

In modern Turkish, ğ usually does not sound like a strong consonant such as English g.

In a word like kâğıdı / kâğıdını, it often:

• lengthens the previous vowel a little, or
• creates a smooth glide between vowels

So kâğıdı is pronounced roughly like kaa-uh-duh or kaa-y-duh, depending on accent and speaking style, but not with a hard g sound.

For learners, the important thing is:

• do not pronounce ğ like English g in go
• keep the sound smooth and light