Skisporene er tydelige.

It is a compound noun plus a definite plural ending:

• ski = ski
• spor = track / trace
• skispor = ski track / ski trail mark
• skisporene = the ski tracks

So skisporene is basically ski-tracks-the, which is a very normal Norwegian way of expressing the ski tracks.

In Norwegian, definiteness is often shown by an ending on the noun instead of a separate word.

Here:

• skispor = ski tracks / ski track(s) in an indefinite sense
• skisporene = the ski tracks

The ending -ene marks definite plural.

So English uses a separate word:

• the ski tracks

But Norwegian usually attaches that meaning to the noun:

• skisporene

The base noun is et spor (a track / a trace), which is a neuter noun.

Its forms are:

• et spor = a track
• sporet = the track
• spor = tracks
• sporene = the tracks

With ski added as a compound:

• et skispor = a ski track
• skisporet = the ski track
• skispor = ski tracks
• skisporene = the ski tracks

A useful thing to notice: spor has the same form in singular indefinite and plural indefinite.

Because the subject is plural.

The adjective tydelig changes form to agree with what it describes:

• tydelig = common gender singular
• tydelig = neuter singular in many predicate uses?
• tydelig/t ydeligt? Actually, the standard neuter form is tydelig? No — for this adjective, the neuter form is tydelig in some speech, but in standard Bokmål the neuter predicate form is usually tydelig?
  Better practical pattern for learners:
• tydelig = singular
• tydelig / tydeligt is not the form used here
• tydelige = plural

Most importantly for this sentence:

• Skisporet er tydelig. = The ski track is clear.
• Skisporene er tydelige. = The ski tracks are clear.

So -e is there because skisporene is plural.

Er is the present tense of å være (to be).

So:

• er = is / are

In this sentence:

• Skisporene er tydelige.
• The ski tracks are clear.

Because the subject is plural in English, we translate er as are, even though Norwegian uses the same form er for both singular and plural.

Here tydelige means something like:

• clear
• distinct
• easy to see
• plain/obvious

With tracks, it usually means the tracks are clearly visible or easy to make out.

So depending on context, Skisporene er tydelige could mean:

• The ski tracks are clear.
• The ski tracks are distinct.
• The ski tracks are easy to see.

Yes. It follows the basic pattern:

• Subject + verb + adjective/complement

So:

• Skisporene = subject
• er = verb
• tydelige = complement

This is the most neutral, natural word order for a simple statement.

A rough English-friendly guide would be:

• skisporene ≈ SHEE-spoo-reh-neh
• er ≈ a very short air / ehr
• tydelige ≈ TYOO-deh-lee-geh or TYOO-deh-lih-geh, depending on accent

A few helpful notes:

• ski in Norwegian sounds like shee, not like English skee
• y is a rounded vowel that English does not really have, so ty- may be tricky at first
• the final -e in Norwegian is usually pronounced as a soft uh-like sound

Yes, if the context already makes it clear that you mean ski tracks.

Compare:

• Skisporene er tydelige. = The ski tracks are clear.
• Sporene er tydelige. = The tracks are clear.

The second sentence is more general. It could refer to ski tracks, footprints, animal tracks, tire tracks, or other traces, depending on context. Using skisporene makes the meaning more specific.