Trykktesten følger batteribyttet.

Those endings are the definite articles attached to the nouns.

• trykktest = pressure test

• trykktesten = the pressure test

• batteribytte = battery replacement / battery change
• batteribyttet = the battery replacement

In Norwegian, the is usually added to the end of the noun instead of being a separate word like in English.

Here:

• -en is the definite ending for many masculine nouns
• -et is the definite ending for many neuter nouns

So the sentence is literally structured like:

• trykktesten = the pressure test
• følger = follows
• batteribyttet = the battery replacement

Because Norwegian usually marks definiteness with a suffix, not a separate article.

Compare:

• en test = a test

• testen = the test

• et bytte = a replacement / a change
• byttet = the replacement / the change

So instead of saying something like the pressure test, Norwegian often says trykktesten as one word.

Følger is the present tense of the verb å følge.

• å følge = to follow
• følger = follows / is following

A useful thing for English speakers: Norwegian verbs do not change by person the way English verbs sometimes do.

So:

• jeg følger = I follow
• du følger = you follow
• han følger = he follows
• vi følger = we follow

The verb form stays følger for all persons in the present tense.

Here it most naturally means comes after or takes place after.

So the sentence is about sequence, not necessarily about one thing physically moving behind another.

In this kind of context, følger often means:

• happens next
• follows in order
• comes after

So the idea is that the pressure test is the step that comes after the battery replacement.

Because batteribytte is a compound noun meaning battery replacement or battery change.

It is built like this:

• batteri = battery
• bytte = replacement / changing

Together:

• batteribytte = battery replacement

Then the definite form is:

• batteribyttet = the battery replacement

By contrast, batteriet means the battery, and byttet by itself can mean the replacement or changed/replaced depending on context. So batteriet byttet would not express the same neat compound meaning.

Because Norwegian very often forms compound nouns as a single word.

Here:

• trykk = pressure
• test = test

Together:

• trykktest = pressure test

Then the definite form becomes:

• trykktesten = the pressure test

This is very normal in Norwegian. English often writes similar expressions as two words, but Norwegian frequently joins them into one.

Because the first part of the compound is trykk.

• trykk = pressure
• test = test

When they are combined, the spelling keeps that kk:

• trykk
  • test → trykktest
• definite: trykktesten

This kind of spelling is common in Norwegian compounds. The double consonant is not random; it reflects the original word trykk.

The sentence uses the standard main-clause order:

Subject + Verb + Object

• Trykktesten = subject
• følger = verb
• batteribyttet = object / what it follows

So it works very similarly to English here:

• The pressure test follows the battery replacement.

This sentence is straightforward because the subject comes first.

Yes. Norwegian main clauses follow the V2 rule, which means the finite verb usually comes in the second position.

In your sentence:

• Trykktesten følger batteribyttet.

If you move a time word to the front, the verb still stays second:

• Deretter følger trykktesten batteribyttet.
  or more naturally depending on meaning:
• Etter batteribyttet følger trykktesten.

The important point is that Norwegian often inverts the subject and verb when something other than the subject comes first.

Yes. In many contexts, comes after is a very natural English rendering of følger.

So:

• Trykktesten følger batteribyttet.
• The pressure test comes after the battery replacement.

That may even sound more natural in some types of procedural English. But grammatically, følger still literally means follows.

It is a noun.

Even though it is connected to the action to replace / to change, the form here names the event or procedure itself:

• et batteribytte = a battery replacement
• batteribyttet = the battery replacement

So the sentence is not saying the battery was replaced. It is naming the replacement as a thing or step in a process.

A rough approximation for an English speaker is:

TRYK-teh-sten FUL-ger ba-te-REE-byt-teh

A few notes:

• y in Norwegian is not like English y; it is a rounded vowel that may take practice.
• fø in følger has a vowel sound English does not have exactly.
• The g in følger may sound softer than an English learner expects, depending on dialect.

A more careful learner-friendly breakdown might be:

• trykktesten ≈ TRYKK-test-en
• følger ≈ FURL-ger or FUHL-ger as a rough guide
• batteribyttet ≈ bah-teh-REE-BYT-teh

Exact pronunciation depends somewhat on dialect, but those approximations can help you get started.