Prima di cuocere le patate, metto la casseruola sul fornello.

Because prima di + infinitive is the normal way to say before doing something in Italian.

• prima di cuocere le patate = before cooking the potatoes

After prima di, Italian normally uses the infinitive when the subject is the same as the main clause, or when the subject is understood generally.

So:

• Prima di partire, chiudo la porta.
• Before leaving, I close the door.

If the subject changes, Italian usually switches to prima che + subjunctive:

• Prima che le patate cuociano, preparo la tavola.
• Before the potatoes cook / are cooked, I set the table.

Not exactly.

• cuocere = to cook in the sense of to heat until done
• cucinare = to cook in the broader sense of to prepare food

So cuocere le patate focuses on the potatoes actually being cooked by heat.

Examples:

• Cuocio le patate = I cook the potatoes
• Cucino le patate = I prepare/cook the potatoes

Both can be possible in some contexts, but cuocere is a bit more precise here.

Italian uses definite articles more often than English.

So where English may say:

• before cooking potatoes

Italian often says:

• prima di cuocere le patate

Here le means the, but it does not always sound as specific in Italian as the does in English. It can simply refer to the potatoes involved in the situation.

This is very common with food and everyday objects.

Because Italian usually drops subject pronouns when they are not needed.

The verb ending already tells you who the subject is:

• metto = I put / I place

So io metto is possible, but usually unnecessary unless you want emphasis or contrast:

• Io metto la casseruola, tu lavi le patate.
• I put the pot on, you wash the potatoes.

Italian often uses the present tense just as English does for:

• habitual actions
• step-by-step descriptions
• instructions in a natural style
• actions being described as part of a routine

So metto la casseruola sul fornello simply means I put the pot on the burner.

Depending on context, it could mean:

• I put
• I’m putting
• I put it on first as part of a routine

Italian present tense is quite flexible.

Casseruola is a cooking vessel, usually something like:

• a saucepan
• a pot
• a casserole pot

The exact English word depends on context. It does not necessarily mean the finished baked dish called a casserole in English.

So in this sentence, think of casseruola as a pot/pan used for cooking.

sul is the contraction of:

• su + il = sul

So:

• sul fornello = on the burner

fornello means the stove burner, hob, or cooking ring.

This is the natural preposition because the pot is placed on the burner, not in it.

So:

• metto la casseruola sul fornello
• I put the pot on the burner

Italian often uses articles where English might use none, or where English relies more on context.

Here:

• la casseruola = the pot
• il fornello = the burner

This usually refers to the relevant pot and burner in the situation. Italian prefers to make nouns sound complete with an article in many everyday sentences.

So even if English might sometimes say something shorter in a recipe-like style, Italian naturally keeps the articles.

Yes, absolutely.

Both are correct:

• Prima di cuocere le patate, metto la casseruola sul fornello.
• Metto la casseruola sul fornello prima di cuocere le patate.

The difference is mainly emphasis.

Starting with Prima di cuocere le patate highlights the sequence first:

• Before cooking the potatoes...

Putting it at the end sounds a little more neutral and straightforward.

It is very common and usually helpful, but not always strictly required.

Because Prima di cuocere le patate is an introductory phrase, a comma makes the sentence easier to read:

• Prima di cuocere le patate, metto la casseruola sul fornello.

Without the comma, many people would still understand it, but the version with the comma is better punctuation.

No. It can also be used before nouns.

Examples:

• prima di cena = before dinner
• prima del lavoro = before work
• prima di uscire = before going out

So:

• prima di + infinitive = before doing something
• prima di + noun = before something

That makes prima di a very useful expression in Italian.