Sfoglio una rivista mentre aspetto il tram.

In Italian, the verb ending usually tells you who the subject is, so the subject pronoun is often omitted.

• sfoglio = I flip through / I leaf through
• aspetto = I wait / I am waiting

Both verb forms clearly mean I, so io is not necessary.

You could say Io sfoglio una rivista mentre aspetto il tram, but that would usually add emphasis, such as I flip through a magazine...

They are both in the present indicative.

• sfoglio comes from sfogliare
• aspetto comes from aspettare

In Italian, the present tense is used more broadly than in English. It can mean:

• a general present: I flip through a magazine while I wait for the tram
• an action happening now: I’m flipping through a magazine while I’m waiting for the tram
• even a habitual action in the right context

So this one tense can cover both English I flip through and I’m flipping through.

Sfogliare usually means to leaf through, to flip through, or to browse through pages quickly, without necessarily reading everything carefully.

So Sfoglio una rivista suggests something like:

• I leaf through a magazine
• I flip through a magazine
• I browse a magazine

It is different from leggo una rivista, which means I read a magazine and sounds more like actual reading.

This is about indefinite and definite articles.

• una rivista = a magazine
  This is indefinite: any magazine, not a specific one.

• il tram = the tram
  This is definite: the specific tram the speaker is waiting for.

In context, the tram is natural because the speaker usually has a particular tram in mind, even if English sometimes uses either the tram or a tram depending on context.

Mentre means while.

It connects two actions happening at the same time:

• Sfoglio una rivista
• aspetto il tram

So mentre shows simultaneity: one action is happening during the other.

It is a very common way to say while in Italian.

Because aspettare in Italian normally takes a direct object.

So Italian says:

• aspetto il tram
• literally: I wait the tram

But natural English requires for:

• I wait for the tram

This is a common difference between English and Italian. With aspettare, you usually do not use a preposition before the thing or person you are waiting for.

Other examples:

• Aspetto Maria = I’m waiting for Maria
• Aspettiamo l’autobus = We’re waiting for the bus

Yes. Sto aspettando il tram is also correct.

Italian has two common ways to express an action in progress:

• aspetto il tram
• sto aspettando il tram

The first is very common and often enough by itself. Italian uses the simple present much more than English does.

The second, with stare + gerundio, emphasizes that the action is in progress right now:

• Sfoglio una rivista mentre sto aspettando il tram

That is grammatical, but often a bit less natural than the simpler mentre aspetto il tram, unless you want to stress the ongoing nature of the waiting.

It can mean either, depending on context.

Italian present tense is flexible.

It could mean:

• right now: I’m flipping through a magazine while I wait for the tram.
• habitually: I flip through a magazine while I wait for the tram.

Without extra context, both are possible. In everyday language, listeners understand the intended meaning from the situation.

Yes. Italian word order is fairly flexible.

You can also say:

• Mentre aspetto il tram, sfoglio una rivista.

This means the same thing. The difference is mainly one of focus or rhythm:

• Sfoglio una rivista mentre aspetto il tram starts with the main action
• Mentre aspetto il tram, sfoglio una rivista starts with the time/background part

Both are natural.

Because tram is a masculine singular noun that takes il.

Italian uses:

• il before many masculine singular nouns
• lo before masculine singular nouns beginning with certain sounds, such as z, s + consonant, ps, gn, and a few others

Examples:

• il tram
• il libro
• lo studente
• lo zaino

Since tram begins with a simple tr sound, the correct article is il.

Yes, gli is tricky for English speakers.

Sfoglio is pronounced roughly like SFO-lyo, with the gli sounding somewhat like the lli in million, but not exactly the same.

A rough breakdown:

• sfo-
• -glio

The gli sound in Italian is a special palatal sound. It also appears in words like:

• famiglia
• figlio
• moglie

It is one of those sounds worth listening to from native speakers and repeating, because English does not have an exact equivalent.