Oyuncu ya sayı kilidini ya da şifre çarkını denedi.

It means either ... or ....

So:

• ya sayı kilidini ya da şifre çarkını = either the combination/number lock or the cipher wheel

This structure usually presents two alternatives. In many contexts, it suggests a choice between them rather than both.

That is a common Turkish pairing:

• ya X ya da Y = either X or Y

Here:

• ya sayı kilidini
• ya da şifre çarkını

Turkish often uses this exact pattern. You may also see slightly different versions in real life, but ya ... ya da ... is a very standard and natural way to say either ... or ....

Also, ya da by itself often just means or.

They are direct objects, and here they are in the accusative form.

The verb denemek means to try, and what is being tried is:

• sayı kilidini
• şifre çarkını

The accusative often appears when the object is specific or definite.

But there is an extra detail here: these are not just simple nouns. They are noun compounds, so the endings stack up.

For example:

• sayı kilidi = number lock
• şifre çarkı = cipher wheel / code wheel

Then, when they become accusative:

• sayı kilidi → sayı kilidini
• şifre çarkı → şifre çarkını

So the final -ni / -nı is the accusative marker added to a possessed/compound form.

Because of a common sound change in Turkish.

The base noun is kilit = lock.
In the compound sayı kilidi, the second noun takes a suffix, and when a vowel-initial suffix is added, the final t often changes to d:

• kilit → kilidi

Then the accusative is added:

• kilidi
  • -ni → kilidini

So:

• kilit = lock
• kilidi = its lock / lock in a compound form
• kilidini = that lock as a specific direct object

This kind of t → d change is very common in Turkish.

Because Turkish commonly forms compound nouns in the order:

first noun + second noun-with-compound ending

So:

• sayı kilidi = literally something like number lock
• şifre çarkı = cipher/code wheel

The first noun describes the type, and the second noun is the main item.

This is a very common Turkish pattern:

• kapı kolu = door handle
• araba kapısı = car door
• telefon numarası = phone number

So sayı kilidi and şifre çarkı are normal compound-noun structures.

Denedi is the simple past tense of denemek = to try.

Breakdown:

• dene- = verb stem
• -di = past tense
• third person singular has no extra ending here

So:

• denedim = I tried
• denedin = you tried
• denedi = he/she/it tried

In this sentence:

• Oyuncu ... denedi = The player tried ...

Turkish does not use articles the same way English does.

There is no direct equivalent of the in ordinary Turkish grammar, and a/an is often not expressed unless needed.

So oyuncu can mean:

• player
• the player

depending on context.

Also, the accusative on kilidini and çarkını helps show that these are specific objects, which often corresponds to English the.

So even without a separate word for the, Turkish still shows definiteness in other ways.

Usually, yes: ya ... ya da ... normally suggests either one or the other.

So the natural reading is:

• the player tried the number lock
• or the player tried the cipher wheel

and not both.

That said, in real life, context always matters. But if you saw this sentence by itself, the most natural interpretation is an either/or choice.

Because Turkish often puts the subject near the beginning and the verb at the end.

So the basic pattern here is:

• Oyuncu = subject
• ya sayı kilidini ya da şifre çarkını = object phrase
• denedi = verb

This is a very normal Turkish word order.

Turkish word order is somewhat flexible, but the verb often stays at the end, especially in neutral statements.

Yes, Turkish allows some flexibility, but changing the order can change the emphasis.

The neutral version is:

• Oyuncu ya sayı kilidini ya da şifre çarkını denedi.

You could move parts around for focus, but the original sentence sounds natural and straightforward.

For a learner, it is best to understand this version as:

Subject + either/or object + verb

That is a very good default pattern to learn.

This is because of vowel harmony.

Turkish suffix vowels change to match the vowels in the word.

• kilidi ends with a front-vowel pattern, so the accusative becomes -ni
• çarkı ends with a back-vowel pattern, so the accusative becomes -nı

That is why you get:

• kilidini
• çarkını

This kind of vowel matching is one of the most important features of Turkish grammar.