Eu encontro os amigos no mercado depois do almoço.

The pronoun Eu (I) is optional in Portuguese because the verb ending -o in encontro already tells you the subject is “I.” You can safely drop it in everyday speech:
– Encontro os amigos no mercado depois do almoço.
Including Eu adds emphasis or clarity, but it’s not required.

Yes, the verb encontrar can mean both “to meet” and “to find.” Context decides which sense you use. In
– Eu encontro os amigos…
you’re saying “I meet the friends” (arranged meeting), not “I find the friends” (locating lost friends). If you meant “I find the keys,” for example, you’d say Eu encontro as chaves.

Portuguese typically uses the definite article before nouns when referring to a specific group.
– os amigos = “the (specific) friends”
If you drop the article (amigos), it’s more general (“friends” as a concept). Use os when you mean particular people you know.

Portuguese contracts prepositions with definite articles:
– em + o → no
– em + a → na
So you must write no mercado, not em o mercado. Similarly, de + o → do, de + a → da.

To express where you meet someone, you normally use em (in/at).
– Eu encontro os amigos em casa.
Para indicates direction (“to”):
– Vou para o mercado. (“I’m going to the market.”)
A can be used with certain verbs (ex.: vou à escola, “I go to school”), but for meeting at a location, stick with em → no/na.

Depois means “after.” When followed by a masculine noun, you contract de + o → do, so:
– depois do almoço = “after lunch.”
You can also say após o almoço, which is slightly more formal and doesn’t contract. Both are correct.

Yes. Portuguese allows time or place phrases at the beginning for emphasis or style:
– Depois do almoço, encontro os amigos no mercado.
– Após o almoço, encontro os amigos no mercado.
Both orders are natural.

Technically possible, but unusual. Standard word order is Subject–Verb–Object–Adverbial:
– Eu encontro os amigos no mercado depois do almoço.
Moving no mercado before os amigos can sound odd unless you really want to stress the location.

Absolutely. The periphrastic future (vou + infinitive) indicates a planned action:
– Vou encontrar os amigos no mercado depois do almoço.
This means “I’m going to meet the friends at the market after lunch.” The simple present encontro can also imply near future in conversational Portuguese, but vou encontrar is crystal-clear.