Etterpå fylte vi bensin og la handleposene i bagasjerommet.

Because Norwegian usually follows the V2 rule in main clauses: the finite verb must come in the second position.

So when Etterpå is placed first, the verb fylte comes next, and the subject vi comes after it:

• Etterpå fylte vi bensin.

If you start with the subject instead, then you get:

• Vi fylte bensin etterpå.

Both are possible, but the word order changes because Norwegian is stricter than English about this.

Etterpå means afterward, after that, or later.

In this sentence, it sets the time for the whole action:

• Etterpå fylte vi bensin og la handleposene i bagasjerommet.

You can also place it later in the sentence:

• Vi fylte bensin etterpå.

When it comes first, it gives a little more emphasis to the time sequence. When it comes later, it sounds more neutral.

Fylte is the past tense of å fylle, which means to fill.

So:

• å fylle = to fill
• fyller = fill / am filling
• fylte = filled
• har fylt = have filled

In this sentence, fylte tells you the action happened in the past.

Yes, it can be used that way. Fylte bensin means something like put petrol in the car or filled up with petrol.

Norwegian can express this in a few ways, for example:

• fylle bensin
• fylle tanken med bensin
• tanke

So this sentence is understandable and natural, though in everyday speech many people would also say vi tanket for we refueled / we got gas.

Also notice that bensin is a mass noun, so there is no article here. Just as in English you say we bought milk, not we bought a milk, Norwegian says fylte bensin rather than adding an article.

In Norwegian, the definite article is often attached to the end of the noun instead of being a separate word.

So:

• handleposer = shopping bags
• handleposene = the shopping bags

And:

• bagasjerom = trunk / boot
• bagasjerommet = the trunk / boot

This is very common in Norwegian. English uses a separate word, but Norwegian often uses an ending instead.

Because handleposene is the definite plural form: the shopping bags.

Here are the forms:

• en handlepose = a shopping bag
• handleposen = the shopping bag
• handleposer = shopping bags
• handleposene = the shopping bags

The sentence is referring to specific bags that the speakers already have, so the definite form is used.

La is the past tense of å legge, which means to lay, to put, or to place.

So:

• å legge = to put / lay
• legger = put / puts / am putting
• la = put / laid
• har lagt = have put / laid

In this sentence, la handleposene i bagasjerommet means put the shopping bags in the trunk.

This verb is important because it is different from å ligge:

• å legge = to put something somewhere
• å ligge = to be lying / to be located

Compare:

• Vi la posene i bagasjerommet. = We put the bags in the trunk.
• Posene lå i bagasjerommet. = The bags were lying in the trunk.

That difference is a very common thing for learners to notice.

The preposition i usually means in or into, depending on context.

Here it is used because the bags are being placed inside the trunk:

• la handleposene i bagasjerommet

With a verb of movement or placement like legge, English often uses into, but Norwegian still commonly uses i.

So although English might say put the bags into the trunk, Norwegian naturally says la posene i bagasjerommet.

Yes. The subject vi applies to both verbs:

• fylte
• la

So the sentence means:

• We filled up with gas and put the shopping bags in the trunk.

Norwegian often avoids repeating the subject when the same subject does both actions. So you do not need to say og vi la unless you want extra emphasis.