Suunnistamme kartan avulla riippumatta siitä, näkyykö reittimerkintä selvästi.

Because -mme is the Finnish personal ending for we.

• suunnistaa = to navigate / to do orienteering
• suunnistamme = we navigate

So the verb already tells you the subject is we, which is why Finnish often leaves out the pronoun me.

The basic form is suunnistaa.

This is the verb you would look up in a dictionary. In this sentence it is in the 1st person plural present tense:

• minä suunnistan = I navigate
• me suunnistamme = we navigate

kartan avulla is a very common structure meaning with the help of a map or using a map.

Here:

• kartta = map
• kartan = the genitive form of kartta
• avulla = by means of, with the help of

So X:n avulla means with the help of X.

Examples:

• veitsen avulla = with the help of a knife
• tietokoneen avulla = using a computer

So kartan avulla is the natural Finnish way to say using a map.

kartan is in the genitive singular.

That is because the postposition avulla requires the word before it to be in the genitive:

• kartta → kartan avulla
• kompassi → kompassin avulla

This is something you learn as part of the whole expression X:n avulla.

It means regardless of that or more naturally regardless of whether...

Very literally, riippumatta comes from a form meaning without depending, so:

• riippumatta siitä = without depending on that

In actual English, you usually translate the whole expression more naturally:

• regardless of whether...
• whether or not...

So in this sentence, it introduces a condition that does not affect the main action.

Because riippumatta siitä, että / onko / näkyykö... is a standard Finnish pattern.

The siitä is the elative form of se (from it / about it / on it, depending on context), but here you should mostly learn the whole linking structure as a set phrase:

• riippumatta siitä, ... = regardless of the fact that / regardless of whether ...

So this is less about translating siitä word-for-word and more about recognizing the whole grammatical pattern.

Because Finnish uses the -ko/-kö form not only for direct questions, but also for embedded yes/no questions.

Here:

• näkyy = is visible / can be seen
• näkyykö = whether it is visible

So the clause näkyykö reittimerkintä selvästi means:

• whether the route marker is clearly visible

This is similar to English whether.

Compare:

• Näkyykö reittimerkintä? = Is the route marker visible?
• En tiedä, näkyykö reittimerkintä. = I don’t know whether the route marker is visible.

That is normal in Finnish yes/no question structure.

In a basic statement:

• Reittimerkintä näkyy selvästi. = The route marker is clearly visible.

In a yes/no question or embedded yes/no question:

• Näkyykö reittimerkintä selvästi?
• ... näkyykö reittimerkintä selvästi.

So the verb comes first, and the -ko/-kö attaches to the verb.

It is a compound noun:

• reitti = route
• merkintä = marking, mark, sign

So reittimerkintä means something like:

• route marking
• trail marker
• route sign

The exact English translation depends on context, but grammatically it is just one compound noun.

Because it is the subject of the verb näkyä here, and the sentence refers to the route marking as a whole thing.

• reittimerkintä näkyy = the route marker is visible

Finnish often uses the nominative subject in this kind of sentence when talking about a definite, whole item.

If the meaning were more indefinite or partial, another form might appear in other contexts, but here the basic nominative reittimerkintä is the natural choice.

Because selvästi is an adverb, and it modifies the verb näkyykö.

• selvä = clear (adjective)
• selvästi = clearly (adverb)

So:

• reittimerkintä on selvä = the route marker is clear
• reittimerkintä näkyy selvästi = the route marker is clearly visible

In this sentence, we need the adverb because it describes how it is visible.

näkyä usually means to be visible, to be seen, or to show in the sense of appearing to the eye.

It is not exactly the same as nähdä:

• nähdä = to see
• näkyä = to be visible / to be seen

So:

• Näen reittimerkinnän. = I see the route marker.
• Reittimerkintä näkyy. = The route marker is visible.

That is why reittimerkintä is the subject here: the marker is the thing that is visible.

Because that part is a subordinate clause attached to the main clause through riippumatta siitä.

Main clause:

• Suunnistamme kartan avulla = We navigate using a map

Subordinate clause:

• riippumatta siitä, näkyykö reittimerkintä selvästi = regardless of whether the route marker is clearly visible

Finnish normally separates this kind of subordinate clause with a comma.

Yes. Finnish word order is fairly flexible, especially for emphasis.

For example, you could also say:

• Riippumatta siitä, näkyykö reittimerkintä selvästi, suunnistamme kartan avulla.

This means the same thing, but now the regardless of whether... part is placed first for emphasis or style.

The original version is perfectly natural too.