Insomma, domani andiamo al mercato e poi facciamo colazione.

In this sentence, insomma is a discourse word, not a literal part of the action.

It can mean things like:

• so
• anyway
• all in all
• in short

Here, it helps introduce or summarize the plan: So, tomorrow we’re going to the market and then we’re having breakfast.

Italian uses words like insomma very naturally in conversation to organize what someone is saying.

Italian often uses the present tense to talk about the future when the time is already clear.

So:

• Domani andiamo al mercato = Tomorrow we’re going to the market

Because domani already tells you this is in the future, Italian does not need a future-tense verb here.

This is very common in everyday speech. English does something similar with I’m going tomorrow.

You could also say:

• Domani andremo al mercato

but the present tense sounds very natural and common.

Italian usually omits subject pronouns when they are not needed.

The verb ending already tells you who the subject is:

• andiamo = we go / we are going
• facciamo = we do / we are doing / we have

So noi is understood automatically.

You can add noi for emphasis or contrast:

• Noi andiamo al mercato, loro restano a casa.
  We are going to the market, they are staying home.

But in a normal sentence, leaving out the pronoun is the standard pattern.

The Italian present tense often covers both the simple present and the present progressive meanings that English separates.

So andiamo can mean:

• we go
• we are going

Which one sounds best depends on the context.

In this sentence, because of domani, the natural English translation is something like:

• Tomorrow we’re going to the market

So the Italian present tense is flexible, and English has to choose the most natural wording.

Al = a + il, which usually means to the.

So:

• andare al mercato = to go to the market

In Italian, many places commonly take a preposition plus article:

• al supermercato = to the supermarket
• al cinema = to the cinema/movie theater
• al mare = to the seaside

So al mercato is the normal expression here.

Al is a contraction of:

• a
  • il = al

This is very common in Italian. Prepositions often combine with definite articles:

• a + il = al
• a + lo = allo
• a + la = alla
• a + i = ai
• a + gli = agli
• a + le = alle

So al mercato literally breaks down as to the market.

In Italian, the usual expression is fare colazione, literally to do/make breakfast, but meaning to have breakfast.

So:

• faccio colazione = I have breakfast
• facciamo colazione = we have breakfast

This is just the standard idiom. English says have breakfast, while Italian says do/make breakfast.

Similarly:

• fare pranzo is not normally used in the same way
• but pranzare = to have lunch
• cenare = to have dinner

So fare colazione is one of those expressions you should learn as a set phrase.

In the expression fare colazione, Italian normally does not use an article.

So you say:

• fare colazione = to have breakfast

not:

• fare la colazione in normal everyday usage

This is because it functions as a fixed expression.

You may sometimes see an article in more specific situations, but for the general meaning to have breakfast, the usual form is simply fare colazione.

Poi means then or afterwards.

It links the two actions in sequence:

1. andiamo al mercato = we go to the market
2. poi facciamo colazione = then we have breakfast

So it shows the order of events.

Yes, Italian word order is flexible, though some versions sound more natural than others.

This sentence is natural because it goes:

• discourse marker: Insomma
• time: domani
• main action: andiamo al mercato
• next action: e poi facciamo colazione

You could also say:

• Domani andiamo al mercato e poi facciamo colazione.
• Andiamo al mercato domani e poi facciamo colazione.

But putting domani early is very common, because it sets the time frame right away.

Yes, slightly.

• poi = then / afterwards
• e poi = and then

In your sentence, e poi connects the second action smoothly to the first one:

• andiamo al mercato e poi facciamo colazione
  we go to the market and then we have breakfast

You could often say just poi, but e poi sounds especially natural when listing events.

It would be:

• Insomma, domani noi andiamo al mercato e poi facciamo colazione.

This is grammatically correct, but it usually sounds more emphatic than necessary.

Adding noi suggests something like:

• we, specifically, are doing this
• perhaps in contrast with someone else

In neutral conversation, Italian normally prefers:

• Insomma, domani andiamo al mercato e poi facciamo colazione.

without noi.