hukusi to sankakukin wo tukau.

It is read:

ふくし と さんかくきん を つかう。

• 副子 = ふくし
• 三角巾 = さんかくきん
• 使う = つかう

と connects nouns and means and.

So:

• 副子と三角巾 = a splint and a triangular bandage

In this sentence, と is simply listing the two things being used.

Because 副子と三角巾 forms one combined object of the verb 使う.

So the structure is:

• [副子と三角巾] を 使う
• use [a splint and a triangular bandage]

Japanese does this very naturally. You do not need to say:

• 副子を三角巾を使う ❌

That is incorrect here.

を marks the direct object of the verb.

The verb is 使う (to use), and the thing being used is:

• 副子と三角巾

So を shows that these are the items being used.

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

So 副子と三角巾を使う。 could mean things like:

• Use a splint and a triangular bandage.
• I use a splint and a triangular bandage.
• We use a splint and a triangular bandage.

The exact subject depends on the situation. In instructions or medical guidance, omitting the subject is very common.

使う is the plain form, also called the dictionary form.

This form is often used in:

• casual speech
• written notes
• instructions
• headings or manual-style language

If you want a polite version, you could say:

• 副子と三角巾を使います。

If you want an instruction like Please use..., you could say:

• 副子と三角巾を使ってください。

Yes. Japanese usually puts the verb at the end.

English:

• Use a splint and a triangular bandage.

Japanese:

• 副子と三角巾を使う。
• literally: splint and triangular-bandage object-marker use

So the basic pattern here is:

• noun + noun + object marker + verb

Usually, と is better here.

• と gives a complete, specific list: A and B
• や gives a partial list: A and B and so on / things like A and B

So:

• 副子と三角巾を使う。 = use a splint and a triangular bandage
• 副子や三角巾を使う。 = use things like splints and triangular bandages

In a precise instruction, と is the natural choice.

Not exactly by grammar alone, but it can feel instructional depending on context.

By itself, 使う is plain non-past, which can express:

• a statement
• a general action
• an instruction in note/manual style

So in a first-aid manual, 副子と三角巾を使う。 can function like an instruction. But a more direct command would be:

• 副子と三角巾を使え。 very direct/strong
• 副子と三角巾を使ってください。 polite request/instruction

No. Normal Japanese writing usually does not use spaces between words.

So this would normally be written as:

副子と三角巾を使う。

Spaces are often added only in teaching materials to make the sentence easier to read.

Yes. 副子（ふくし） is a medical term meaning splint. It sounds technical or clinical.

In everyday conversation, people may be more familiar with other expressions depending on the context, but in medical or first-aid writing, 副子 is perfectly natural.

No. With と, it normally means use both.

So 副子と三角巾を使う means:

• use a splint and a triangular bandage

If you wanted to express either A or B, you would need a different structure.