tyeenkabaa wo tukeru.

Because チェーンカバー is a loanword-style noun made from foreign-origin words:

• チェーン = chain
• カバー = cover

Katakana is commonly used for this kind of vocabulary in Japanese. It can also make product parts and mechanical terms sound natural, especially in manuals, labels, and instructions.

を marks the direct object of the verb.

So in チェーンカバーを付ける, the thing being attached is チェーンカバー.

A very literal breakdown is:

• チェーンカバー = chain cover
• を = object marker
• 付ける = attach / put on / install

So the sentence structure is basically [thing] + を + [do to it].

付ける is a very common verb meaning to attach, to put on, to fasten, or to install, depending on context.

For a part like a chain cover, 付ける is natural because you are attaching it to something.

By contrast:

• 入れる means to put in
• 置く means to place / put down

So 付ける fits the idea of mounting or fastening a part.

It is read つける.

So the whole sentence is read:

チェーンカバーをつける。

This is a very common verb, and it appears in many meanings depending on context, such as:

• 電気を付ける = turn on the light
• 名前を付ける = give a name
• 気を付ける = be careful
• アクセサリーを付ける = put on / wear accessories

Here, it means attach / install.

The dictionary form is very common in:

• instruction manuals
• labels
• step-by-step procedures
• captions
• neutral descriptions of actions

So チェーンカバーを付ける。 sounds like a manual or instruction-step style sentence: Attach the chain cover.

If you wanted to make it polite, you could say:

チェーンカバーを付けます。

If you wanted a more direct command, you might see:

チェーンカバーを付けてください。

Yes. Japanese often leaves out the subject when it is obvious from context.

In a sentence like this, the implied subject could be something like:

• you attach the chain cover
• I/we attach the chain cover
• the next step is to attach the chain cover

In instructions, English often uses an imperative such as Attach the chain cover, while Japanese often just uses the plain dictionary form.

Normally, Japanese is written without spaces.

So the usual way to write this is:

チェーンカバーを付ける。

The spaces in your example are probably there only to help learners see the parts more clearly:

• チェーンカバー
• を
• 付ける

That kind of spacing is common in teaching materials, but not in ordinary Japanese writing.

Yes. Both are possible:

• 付ける
• つける

Using kanji makes the meaning clearer and is very common. Writing it in hiragana is also correct, especially in simple materials or when the writer wants a softer or easier look.

In this sentence, 付ける is the more typical written form.

Japanese usually puts the verb at the end.

So the pattern here is:

object + を + verb

That gives:

チェーンカバーを付ける。

This is different from English, where you would say attach the chain cover with the verb first in an instruction.

You would usually add に to mark the place or target of attachment.

For example:

自転車にチェーンカバーを付ける。
= Attach the chain cover to the bicycle.

So:

• を marks the thing being attached
• に marks the place or thing it is attached to

That is a very common pattern with 付ける.