Stisni ovu tipku ako želiš otvoriti prozor.

Stisni is the imperative form, used for giving a command or instruction to one person:

• stisni = press!
• stisnite = press! (to several people, or polite singular)

By contrast, stisneš is a present-tense form meaning you press or you will press depending on context, not a command.

So in instructions like this, Croatian uses the imperative:

• Stisni ovu tipku. = Press this button.

In Croatian, the subject pronoun is often omitted because the verb ending already shows the person.

• stisni already tells you the speaker is addressing you singular
• želiš also clearly means you want

So ti is unnecessary unless you want extra emphasis:

• Ti stisni ovu tipku... = You press this button...

Most of the time, leaving out the pronoun sounds more natural.

Because ovu tipku is in the accusative case, not the nominative.

The button is the direct object of stisni:

• press what? → this button

So both the adjective/demonstrative and the noun have to change form.

Feminine singular:

• nominative: ova tipka = this button
• accusative: ovu tipku = this button, as an object

This is very common in Croatian:

• Vidim ovu kuću.
• Uzmi ovu knjigu.
• Stisni ovu tipku.

Yes, tipka is a normal and very common word for a button or key, especially on devices, keyboards, remotes, and interfaces.

Depending on context, you may also hear:

• gumb = button
• dugme = button, common in some regions/varieties

Very roughly:

• tipka often suggests a pressable key/button
• gumb can also mean a physical button, including on clothes or machines

In a sentence like this, tipka sounds completely natural.

In standard Croatian, after verbs like željeti = to want, it is very common to use the infinitive:

• želim ići = I want to go
• želiš otvoriti = you want to open

So:

• ako želiš otvoriti prozor = if you want to open the window

A da + present tense construction exists in the wider South Slavic area, but the infinitive is especially typical and standard in Croatian here.

So for a learner, želiš + infinitive is the pattern to remember.

Otvoriti is the infinitive of the verb to open.

It appears after želiš:

• želiš otvoriti = you want to open

This is similar to English want to open, where to open is also an infinitive.

So the structure is:

• ako = if
• želiš = you want
• otvoriti = to open
• prozor = window

Here prozor is also the direct object of otvoriti.

But prozor is a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular is the same as the nominative singular.

So:

• nominative: prozor
• accusative: prozor

That is why you get:

• otvoriti prozor = to open the window

Compare that with an animate masculine noun, where accusative changes:

• vidim čovjeka = I see the man

But:

• vidim prozor = I see the window

It can mean either, depending on context.

• literal: a window in a wall
• digital: a computer window

In a sentence with tipka, many learners might imagine a device or software interface, so prozor could easily mean a computer window. But grammatically the sentence works for both meanings.

Croatian often relies on context for this, just like English does with window.

Ako means if and introduces a condition:

• ako želiš otvoriti prozor = if you want to open the window

This is a very basic and common structure in Croatian:

• Ako imaš vremena, dođi. = If you have time, come.
• Ako želiš, mogu pomoći. = If you want, I can help.

So the sentence is literally structured as:

• Press this button if you want to open the window.

Yes. Croatian word order is more flexible than English word order.

You can also say:

• Ako želiš otvoriti prozor, stisni ovu tipku.

This means the same thing:

• If you want to open the window, press this button.

The original version puts the instruction first:

• Stisni ovu tipku...

The other version puts the condition first:

• Ako želiš otvoriti prozor...

Both are natural.

It is natural, but there are other common choices too.

Possible verbs include:

• stisni = press, squeeze
• pritisni = press
• pritisnite = press, formal/plural

For buttons, many speakers might especially use pritisni or pritisnite in instructions. But stisni ovu tipku is still perfectly understandable and natural.

So the nuance is:

• stisnuti can feel a bit like squeeze/press
• pritisnuti is often the most neutral press

Both are perfective forms, which is very natural here because the sentence is about a single completed action.

• stisni comes from stisnuti = to press once / press to completion
• otvoriti = to open / to get something opened

This fits an instruction manual style:

• do one action
• achieve one result

If you used an imperfective verb, the meaning would shift more toward process, repetition, or general activity.

So perfective aspect is a good match for:

• pressing a button once
• opening a window

The sentence is informal because it uses stisni and želiš, which address one person informally.

A polite or plural version would be:

• Stisnite ovu tipku ako želite otvoriti prozor.

Compare:

• stisni / želiš = singular informal
• stisnite / želite = plural or polite singular

This is similar to the difference between addressing one friend and addressing a customer or a group.

Yes. In English, press and push can both work here.

Croatian stisni mainly tells you to apply pressure to the button. Depending on the device and context, English could naturally say:

• Press this button...
• Push this button...

In learner terms, press is usually the safest equivalent for stisni ovu tipku in this kind of sentence.