Yeni şablonu açınca kısayolun işe yaradığını fark ettim.

Açınca comes from açmak (to open) + the converb suffix -ınca / -ince / -unca / -ünce.

So:

• açmak = to open
• açınca = when opening / when [someone] opens / when [someone] opened

In this sentence, it means something like when I opened or once I opened.

This suffix connects one action to another:

• Kapıyı açınca içeri girdim. = When I opened the door, I went inside.

It does not show person by itself, so the subject is understood from context.

Because şablonu has the accusative ending -u, which marks a specific direct object.

• şablon = template
• şablonu = the template / that specific template

In Yeni şablonu açınca, the speaker is talking about a particular template, not just any template in general.

Compare:

• şablon açmak = to open a template / template(s) in general
• şablonu açmak = to open the template / a specific template

So yeni şablonu means the new template as a definite object.

Turkish often leaves out subject pronouns when they are already clear from the verb or the context.

The main verb is fark ettim:

• ettim = I did
• so the subject is clearly I

Because of that, the first part açınca is naturally understood with the same subject unless something else is stated.

So:

• Yeni şablonu açınca ... fark ettim. = When I opened the new template, I noticed ...

If you wanted to make the subject explicit, you could say:

• Ben yeni şablonu açınca ... fark ettim.

But that is usually unnecessary.

Because kısayolun is the subject of a subordinate clause built with a verbal noun structure.

Here, kısayolun işe yaradığını means:

• that the shortcut worked
• literally, something like the shortcut’s being useful/working

In this kind of structure, the subject of the embedded clause usually takes the genitive ending:

• kısayol = shortcut
• kısayolun = of the shortcut / the shortcut’s

This is very common in Turkish:

• Onun geldiğini biliyorum. = I know that he came.
• Arabanın bozulduğunu gördüm. = I saw that the car broke down.

So kısayolun is not random; it is there because it belongs to the embedded that... clause.

İşe yaramak is a common Turkish expression meaning:

• to work
• to be useful
• to do the job
• to serve its purpose

It is partly idiomatic. Literally, it looks like to be useful for the job/use.

So in this sentence, kısayolun işe yaradığını means:

• that the shortcut worked
• or that the shortcut was useful

It does not mean that the shortcut literally created work.

Because the expression is işe yaramak, not iş yaramak.

The noun iş takes the dative ending -e here:

• iş = work / job / function
• işe = to the job / for use / for a purpose

Some Turkish verbs and expressions require a certain case, and this is one of them. You just learn it as a set phrase:

• işe yarıyor = it works / it is useful
• işe yaramıyor = it doesn’t work / it is useless

So işe is required by the expression.

This is a classic Turkish embedded-clause form.

Yaradığını can be broken down like this:

• yara- = verb stem from yaramak
• -dık = a suffix used to make a noun-like subordinate clause
• -ı = 3rd person possessive marker
• -nı = accusative marker

In surface form, these combine as:

• yara + dık + ı + nı
• → yaradığını

So kısayolun işe yaradığını literally means something like:

• the shortcut’s being useful
• or more naturally, that the shortcut worked

This whole chunk is the object of fark ettim:

• [kısayolun işe yaradığını] fark ettim
• I noticed [that the shortcut worked]

Because Turkish often expresses that-clauses by turning the verb into a noun-like form instead of using a separate conjunction.

English says:

• I noticed that the shortcut worked.

Turkish often says something structurally closer to:

• I noticed the shortcut’s working.

That is what kısayolun işe yaradığını fark ettim is doing.

So instead of a separate word meaning that, Turkish uses the -DIK type structure:

• geldiğini biliyorum = I know that he came
• doğru olduğunu düşündüm = I thought that it was correct

This is one of the biggest structural differences between English and Turkish.

Fark etmek is a compound verb meaning:

• to notice
• to realize

It is written as two words because it is made of:

• fark = difference / notice
• etmek = to do / to make

In the past tense first person singular:

• fark ettim = I noticed / I realized

This pattern is very common in Turkish:

• yardım etmek = to help
• kabul etmek = to accept
• kontrol etmek = to check

So fark ettim is not unusual; it is just a standard compound verb.

The given order is natural and clear, but Turkish word order is fairly flexible.

Current sentence:

• Yeni şablonu açınca kısayolun işe yaradığını fark ettim.

This puts the time/background first:

• When I opened the new template, I noticed that the shortcut worked.

You could also say:

• Kısayolun işe yaradığını yeni şablonu açınca fark ettim.

This gives a little more emphasis to what you noticed.

In Turkish, the verb usually stays at the end, but other parts can move around for emphasis, topic, or style. So the sentence order is flexible, though the original version is very natural.

It can correspond to different English translations depending on context.

In Turkish, this kind of subordinate clause does not always map neatly onto one English tense. So:

• kısayolun işe yaradığını fark ettim

could be understood as:

• I noticed that the shortcut worked
• I noticed that the shortcut was useful
• I noticed that the shortcut works

In a sentence like this, English usually chooses the version that sounds most natural in context. If this is about trying a shortcut and seeing that it functions properly, worked is often the best translation.