Yeni uygulamayı telefonuma yükledim, şimdi daha rahat çalışıyorum.

Because uygulamayı is the definite direct object of the verb yükledim.

• uygulama = app / application
• uygulamayı = the app

In Turkish, when the direct object is specific or definite, it usually takes the accusative suffix. Since the noun ends in a vowel, a buffer y appears before the suffix:

• uygulama + yı → uygulamayı

So this is not just an app, but the new app / that specific new app.

It is the accusative case suffix, used for a definite direct object.

The basic accusative forms are:

• -ı
• -i
• -u
• -ü

Which one appears depends on vowel harmony.
If the noun ends in a vowel, Turkish inserts a buffer consonant y before the suffix.

So:

• uygulama ends in a vowel
• accusative suffix here is -ı
• buffer y is inserted

Result:

• uygulamayı

telefonuma has three parts:

• telefon = phone
• -um = my
• -a = to / onto

So:

• telefonum = my phone
• telefonuma = to my phone / onto my phone

In this sentence, the natural English translation is onto my phone or on my phone, but grammatically Turkish is using the dative case.

Because with yüklemek in this kind of sentence, Turkish marks the destination/target with the dative.

So the structure is roughly:

• something-ACC
• destination-DAT
• yüklemek

Here:

• yeni uygulamayı = the new app
• telefonuma = onto my phone
• yükledim = I installed/loaded

This is very natural Turkish. The dative shows where the app was loaded to.

Because Turkish usually does not need subject pronouns when the verb ending already shows the person.

Here:

• yükledim = I installed
• çalışıyorum = I am working / I work

The endings already tell you the subject is I:

• -dim in yükledim
• -um in çalışıyorum

So adding ben would usually be unnecessary unless you want emphasis.

Because the sentence describes:

1. a completed action in the past
2. a current result or ongoing situation now

So:

• yükledim = I installed it
• şimdi daha rahat çalışıyorum = now I work / am working more comfortably

This is very natural. Turkish often uses past tense for the finished event and present continuous for what is happening now as a result.

yükledim can be broken down as:

• yükle- = load / install
• -di = past tense
• -m = I

So:

• yükledim = I loaded / I installed

The verb dictionary form is yüklemek.

çalışıyorum can be broken down as:

• çalış- = work
• -ıyor = present continuous
• -um = I

So:

• çalışıyorum = I am working / I work

In Turkish, the -iyor form is very common for actions happening now, but it can also sometimes sound natural in English as a simple present depending on context.

Because Turkish often uses the same form for both adjective and adverb.

• rahat bir sandalye = a comfortable chair
• rahat çalışıyorum = I work comfortably

Unlike English, Turkish usually does not add something like -ly.
So in this sentence, rahat is functioning adverbially: it describes how the person works.

daha means more, so:

• rahat = comfortable / comfortably
• daha rahat = more comfortable / more comfortably

In this sentence, it means the speaker can now work more comfortably or more easily than before.

It implies a comparison, even though the earlier situation is not stated explicitly.

şimdi means now.

It connects the first action to the present result:

• First: Yeni uygulamayı telefonuma yükledim
• Then: şimdi daha rahat çalışıyorum

So şimdi highlights the current situation after the installation. It tells the listener that this second clause is true now, as a result of the first one.

Not completely. Turkish word order is flexible, but this sentence follows a very natural pattern.

First clause:

• Yeni uygulamayı telefonuma yükledim
• object + destination + verb

Second clause:

• şimdi daha rahat çalışıyorum
• time word + adverb + verb

The verb often comes at the end in Turkish, which is happening here in both clauses.
You can move some elements for emphasis, but this version sounds neutral and natural.

Because Turkish often joins two closely related clauses with a comma, especially when the relationship is clear from context.

Here the meaning is easy to understand:

• I installed the new app on my phone,
• now I work more comfortably.

A conjunction could also be used, depending on style:

• ..., ve şimdi daha rahat çalışıyorum.
• ...; artık daha rahat çalışıyorum.
• ..., bu yüzden şimdi daha rahat çalışıyorum.

But the comma version is concise and natural.

Several suffixes change shape because of vowel harmony.

Examples from the sentence:

• uygulama + yı → uygulamayı
• telefon + um → telefonum
• telefonum + a → telefonuma
• yükle + di + m → yükledim
• çalış + ıyor + um → çalışıyorum

Turkish suffix vowels adjust to fit the vowels in the word. That is why you do not see one single fixed form for endings like the accusative or possessive suffix.