Buksan mo ang ilaw sa kusina.

A rough breakdown is:

Buksan = open / turn on
mo = you
ang ilaw = the light
sa kusina = in the kitchen

Filipino often puts the verb first, so the structure is more like Turn on you the light in the kitchen, even though the natural English meaning is simply Turn on the light in the kitchen.

Because buksan literally means open, but in Filipino it is also commonly used for turning on things like lights, radios, TVs, and faucets.

So:

Buksan ang pinto = Open the door
Buksan ang ilaw = Turn on the light

The exact English translation depends on what is being opened.

The verb buksan comes from the root bukas and the suffix -an.

That suffix helps form a verb that focuses on the thing being affected. In this sentence, the affected thing is ang ilaw.

So buksan here means something like open/turn on something. That is why ang ilaw is the thing receiving the action.

Mo is the form of you used here because of the verb pattern.

With a verb like buksan, the doer of the action is marked by a genitive pronoun, so you get:

Buksan mo... = You open / turn on ...

By contrast, ikaw and ka are used in other sentence types where you is the topic or subject in a different way.

So mo is the correct choice in this sentence.

Ang marks the topic or focused noun phrase of the sentence.

Here, ang ilaw is the thing being acted on, so it gets ang.

It is often translated with the in English, but ang is not exactly the same as English the. It is a grammar marker, not just an article.

Sa kusina means in the kitchen.

The word sa is a marker used for locations, directions, and places. Depending on context, it can mean in, at, on, or to.

Filipino does not use articles the same way English does, so you do not need a separate word for the before kusina here.

Usually ilaw means the light itself or the light fixture in a general sense.

In this sentence, it naturally means the kitchen light. It does not specifically mean the switch, even though in real life you would probably press a switch to do it.

So the sentence is about turning on the light, not about opening or touching the switch itself.

Because verb-first word order is very common in Filipino.

Especially in commands, it is natural to begin with the verb:

Buksan mo ang ilaw sa kusina.

That is normal Filipino sentence structure. English usually does something similar in commands too, since we say Turn on the light, not You turn on the light.

Yes, it is a command or direct instruction.

By itself, it sounds neutral and straightforward. Whether it feels rude depends a lot on tone of voice and situation.

If you want to make it more polite, you can add polite markers or use a request form, for example:

Buksan po ninyo ang ilaw sa kusina.
Pakibuksan po ang ilaw sa kusina.

Those sound more polite than the plain Buksan mo...

Yes, mo is singular.

If you are speaking to more than one person, or speaking respectfully to one person, you would usually use ninyo instead:

Buksan ninyo ang ilaw sa kusina.

For extra politeness, add po:

Buksan po ninyo ang ilaw sa kusina.

So:

mo = one person, casual/neutral
ninyo = plural or respectful

A rough pronunciation is:

book-SAHN mo ahng ee-LAOW sa koo-SEE-na

A few helpful notes:

bu sounds like boo
ng in ang is one sound, like the end of sing
kusina sounds like koo-SEE-na

You do not need to pronounce every word separately in a stiff way; in normal speech, it flows smoothly together.