Usamos a bússola no percurso.

Yes. Usamos can mean either:

• we use / we are using (present tense), or
• we used (simple past / preterite)

The form is the same in writing for -ar verbs like usar.

So the exact time depends on context. In an isolated sentence, learners often read it as we use or we used, depending on what meaning has already been given.

Examples:

• Usamos a bússola todos os dias. = We use the compass every day.
• Ontem usamos a bússola. = Yesterday we used the compass.

In speech, context usually makes it clear.

Portuguese often leaves out subject pronouns when the verb ending already shows who the subject is.

Here, usamos clearly matches nós = we, so nós is unnecessary.

So both are possible:

• Usamos a bússola no percurso.
• Nós usamos a bússola no percurso.

The version without nós is very natural and common.

You might add nós for emphasis, contrast, or clarity:

• Nós usamos a bússola, mas eles usaram o GPS.

A is the feminine singular definite article, meaning the.

• a bússola = the compass

The noun bússola is feminine, so it takes a, not o.

This is a very common pattern in Portuguese: nouns often appear with a definite article where English may or may not use one.

Examples:

• o mapa = the map
• a lanterna = the torch/flashlight
• a bússola = the compass

No is a contraction of:

• em = in/on/at
• o = the

So:

• no percurso = in the route / along the route / on the course of the journey

This contraction is extremely common in Portuguese:

• em + o = no
• em + a = na
• em + os = nos
• em + as = nas

Examples:

• no carro = in the car
• na estrada = on the road
• nos trilhos = on the paths
• nas montanhas = in the mountains

So no percurso is the natural contracted form.

Percurso usually means route, course, path, or journey, depending on context.

In this sentence, it suggests the route or stretch of travel during which the compass is used.

Possible translations include:

• on the route
• during the journey
• along the path

It is a fairly neutral word and can be used for:

• a physical route
• a planned course
• sometimes even a figurative path

Examples:

• O percurso é difícil. = The route is difficult.
• Mudámos o percurso. = We changed the route.

This is a normal Portuguese sentence order:

• Usamos = verb
• a bússola = direct object
• no percurso = prepositional phrase giving context/location

So the structure is basically: [verb] + [object] + [prepositional phrase]

This is very natural in Portuguese, especially when the subject pronoun is omitted.

You could also rearrange parts for emphasis, but the original order is the most straightforward:

• No percurso, usamos a bússola.
  This puts extra focus on during the route.

A helpful approximate pronunciation is:

• BÚS-so-la

The stress is on the first syllable because of the accent mark: bússola.

A few points:

• ú shows the stressed syllable.
• ss gives an s sound, like in see, not a z sound.
• The final a in European Portuguese is often reduced, so it may sound less open than in many other varieties.

So for an English speaker, something like BOO-suh-luh is a rough guide, though not exact.

The accent mark in bússola shows where the stress falls:

• BÚS-so-la

Without the accent, Portuguese stress rules would lead you to expect a different stress pattern. The written accent helps you pronounce it correctly.

In Portuguese, accent marks often tell you:

• which syllable is stressed
• sometimes also something about vowel quality

So here, the accent is important for correct pronunciation.

Yes. Usar is the normal verb for to use.

So:

• usar a bússola = to use the compass

Very natural alternatives might appear in different contexts, such as:

• servir-se de uma bússola = to make use of a compass
  (more formal or less common in everyday speech)
• orientar-se com uma bússola = to orient oneself with a compass / use a compass to navigate

But for a simple sentence, usamos a bússola is completely natural and standard.

Yes, this sentence is grammatical and natural.

That said, depending on context, a speaker might also say:

• Usámos a bússola durante o percurso. = We used the compass during the journey.
• Usámos a bússola para nos orientarmos. = We used the compass to orient ourselves.
• Levávamos uma bússola no percurso. = We carried a compass on the route.

The original sentence is perfectly fine, but in real conversation people often choose wording that gives a little more context about why the compass was used.