Prima di stampare il documento, controllo ogni pagina.

In Italian, prima di + infinitive is the normal pattern for before doing something.

• prima di stampare = before printing
• prima di uscire = before leaving
• prima di mangiare = before eating

So di is required here before the infinitive stampare.

After prima di, Italian normally uses the infinitive when the subject of both actions is the same.

In this sentence, the same person does both things:

• stampare il documento
• controllo ogni pagina

So Italian uses:

• Prima di stampare il documento, controllo ogni pagina.

If the subject changes, Italian usually uses prima che + a finite verb instead:

• Prima che tu stampi il documento, controllo ogni pagina. = Before you print the document, I check every page.

Italian often leaves out subject pronouns when they are not needed, because the verb ending already shows the subject.

• controllo = I check
• controlli = you check
• controlla = he/she checks

So io controllo is possible, but usually unnecessary unless you want emphasis or contrast.

Controllo is the present indicative of controllare.

Italian uses the present tense in many cases where English also uses the present:

• for habits: Before printing the document, I check every page
• for routines/instructions
• sometimes even for near-future actions, depending on context

Here it most naturally sounds like a routine or usual action.

Italian uses articles more often than English.

So where English may say:

• print the document or sometimes just
• print document (in a very special style, like instructions)

Italian normally says:

• stampare il documento

Leaving out the article here would sound unnatural in standard Italian.

Ogni means every/each, and it is followed by a singular noun:

• ogni pagina = every page
• ogni giorno = every day
• ogni studente = every student

So ogni pagine is incorrect.

They are similar, but not exactly the same.

• ogni pagina = every page / each page
• tutte le pagine = all the pages

In many contexts they are very close:

• Controllo ogni pagina = I check each page
• Controllo tutte le pagine = I check all the pages

Ogni pagina focuses a bit more on the pages one by one; tutte le pagine focuses on the complete set.

The comma separates the introductory clause from the main clause:

• Prima di stampare il documento, = introductory time expression
• controllo ogni pagina. = main clause

This comma is very natural in writing. You may sometimes see punctuation handled a little differently in shorter sentences, but here the comma is standard and helpful.

Yes. Italian allows this sentence to be rearranged.

For example:

• Controllo ogni pagina prima di stampare il documento.

This means the same thing. The version with Prima di stampare il documento first puts more emphasis on the before printing part.

Here controllo is a verb: I check.

It comes from the verb controllare.

Be careful, because controllo can also be a noun in other contexts:

• il controllo = the check / the control / the inspection

But in this sentence, it is clearly the verb because of the structure:

• controllo ogni pagina = I check every page

Yes, often you could.

• controllo ogni pagina = I check every page
• verifico ogni pagina = I verify/check every page

Controllare is very common and general.
Verificare can sound a bit more formal or more like verify / make sure.

In everyday language, controllo is very natural here.

Use prima di + infinitive when the subject is the same for both actions:

• Prima di stampare il documento, controllo ogni pagina.
  • I check
  • I print

Use prima che when the subject is different:

• Prima che tu stampi il documento, controllo ogni pagina.
  • you print
  • I check

This is a very important distinction in Italian.