Ora nos orientamos pela bússola, ora seguimos a sinalização.

Here, ora ... ora ... is a paired structure that shows alternation between two possibilities.

So the sentence means something like:

• sometimes we use the compass, sometimes we follow the signs
• at one moment we go by the compass, at another we follow the signposting

It suggests that the two methods alternate.

Not really.

Although ora can have other uses in Portuguese, in this sentence it is part of the fixed pattern ora ... ora ..., which expresses alternation, not simple time.

So here it is not the everyday English now. It is closer to:

• sometimes ... sometimes ...
• now ... now ... in a more literary English sense

It is perfectly correct and natural, but it sounds a bit more careful, written, or slightly literary than some simpler alternatives.

In more casual speech, people might also say things like:

• às vezes ... outras vezes ...
• umas vezes ... outras ...

So ora ... ora ... is not strange, but it is a bit more stylistically marked.

Because Portuguese usually does not need subject pronouns when the verb ending already shows who the subject is.

Both orientamos and seguimos clearly mean we in this context, so nós can be left out.

You could add nós for emphasis or contrast, but it is not necessary:

• Ora nos orientamos pela bússola, ora seguimos a sinalização.
• Ora nós nos orientamos pela bússola, ora seguimos a sinalização.

The version without nós is more neutral.

Nos is the reflexive pronoun for we / ourselves.

The verb here is orientar-se, which means to orient oneself, to find one’s way, or to get one’s bearings.

So:

• orientar = to guide / direct / orient something or someone
• orientar-se = to orient oneself / find one’s way

That is why nos appears here: the subject is doing the action in relation to itself.

In European Portuguese, clitic pronouns like me, te, se, nos often come after the verb in a simple affirmative sentence:

• Orientamo-nos pela bússola.

However, certain words or structures can pull the pronoun before the verb. In a sentence with the correlative pattern ora ... ora ..., nos orientamos is natural.

So in this sentence, the front position of nos is not surprising.

A learner should mainly remember this:

• standalone neutral sentence: orientamo-nos
• in this kind of structure: nos orientamos can appear naturally

Here they are in the present indicative.

The sentence describes a repeated or habitual situation: we alternate between two ways of navigating.

That said, forms like orientamos and seguimos can also look identical to the preterite in Portuguese. So context is what tells you the tense.

In this sentence, the meaning is clearly present/habitual because of the ora ... ora ... pattern and the general statement being made.

Pela is the contraction of por + a.

So:

• por + a = pela

With orientar-se, Portuguese often uses por to mean by, according to, or using as a guide/reference:

• orientar-se pela bússola = to guide oneself by the compass
• to use the compass as one’s reference

So pela bússola is not just literally through the compass. It means the compass is the thing guiding you.

Yes, you might hear com a bússola, but pela bússola is especially natural with orientar-se.

The difference is roughly this:

• pela bússola = using the compass as your guide/reference
• com a bússola = with the compass, by means of the compass

Both can make sense, but orientar-se pela bússola is the more idiomatic choice here.

A sinalização means the signage, the signposting, or the waymarking.

It does not usually refer to one single sign. It refers to the whole system of signs, markers, or route indications available in that place.

Depending on context, it could mean:

• road signs
• trail markers
• directional signs
• general wayfinding signage

Because sinalização is a collective / mass-type noun.

Portuguese often uses it in the singular to refer to the whole set of signs or markings as one system.

So:

• a sinalização = the signage / the signposting as a whole

This is similar to English signage, which is also often treated as a single concept rather than a countable list of separate signs.

Because seguir normally takes a direct object.

So in Portuguese you say:

• seguir o mapa
• seguir as instruções
• seguir a sinalização

No extra preposition is needed.

This works much like English follow:

• follow the map
• follow the instructions
• follow the signs