Etter buldreøkten ligger kalkposen og klatreskoen ved landingsmatten.

This is because Norwegian is a V2 language in main clauses: the finite verb usually comes in the second position.

Here, Etter buldreøkten is placed first as a time expression, so the verb has to come next:

• Etter buldreøkten = first slot
• ligger = second slot
• kalkposen og klatreskoen = subject

So the sentence structure is:

• Etter buldreøkten ligger kalkposen og klatreskoen ved landingsmatten.

If you started with the subject instead, you would get:

• Kalkposen og klatreskoen ligger ved landingsmatten etter buldreøkten.

Both are grammatical, but the original puts more focus on when.

Etter means after.

In this sentence, Etter buldreøkten means after the bouldering session.

It introduces a time phrase telling you when the rest of the sentence is true.

A few similar examples:

• Etter jobb = after work
• Etter trening = after training
• Etter filmen = after the film

Buldreøkten is a compound noun, which is extremely common in Norwegian.

It is made up of:

• buldre = to boulder / bouldering
• økt = session, workout, period of activity
• -en = the definite singular ending

So:

• buldreøkt = bouldering session
• buldreøkten = the bouldering session

Norwegian usually writes compounds as one word, where English often uses two words or a phrase.

Compare:

• klatresko = climbing shoe
• landingsmatte = landing mat / crash mat

That -en is the definite article attached to the noun.

In English, you usually put the before the noun:

• the chalk bag
• the climbing shoe
• the landing mat

In Norwegian, the definiteness is often added as an ending:

• en kalkpose = a chalk bag

• kalkposen = the chalk bag

• en klatresko = a climbing shoe

• klatreskoen = the climbing shoe

• en landingsmatte = a landing mat
• landingsmatten = the landing mat

So instead of a separate word like the, Norwegian often uses a suffix.

Norwegian often prefers a position verb where English might simply use is/are.

Here, ligger literally means lies / is lying. It is used for things that are in a resting position, especially objects placed somewhere.

So:

• Kalkposen ligger ved landingsmatten. = The chalk bag is lying by the landing mat.

This is more natural in Norwegian than just using er.

A rough comparison:

• er = exists / is
• ligger = is lying / is located in a lying position
• står = is standing
• sitter = is sitting

Norwegian uses these a lot more than English does.

Ved means something like by, beside, or near.

So:

• ved landingsmatten = by the landing mat / next to the landing mat

It suggests location close to something, but not necessarily on top of it.

Compare:

• ved matten = by the mat
• på matten = on the mat
• i hallen = in the gym/hall

So ved is the right choice if the items are located next to the mat.

Because kalkposen og klatreskoen is a single combined subject: the chalk bag and the climbing shoe.

Just like in English, one verb can apply to both:

• The bag and the shoe lie by the mat.

In Norwegian, the present tense verb does not change form for singular vs. plural:

• Kalkposen ligger ...
• Klatreskoen ligger ...
• Kalkposen og klatreskoen ligger ...

So ligger works for all of them.

Yes.

It is made from:

• landing = landing
• matte = mat
• -en = the definite singular ending

So:

• landingsmatte = landing mat
• landingsmatten = the landing mat

Again, Norwegian normally writes this as one word, while English might use two.

This is one of the most important habits to get used to in Norwegian: if English has a noun + noun combination, Norwegian often makes it a single compound word.

Yes. A natural alternative would be:

• Kalkposen og klatreskoen ligger ved landingsmatten etter buldreøkten.

That is also grammatical.

The difference is mainly focus:

• Etter buldreøkten ... emphasizes the time
• Kalkposen og klatreskoen ... emphasizes the objects

Norwegian allows this kind of flexibility, but the finite verb still stays in second position in a main clause.

Literally, klatreskoen is the climbing shoe in the singular.

If you mean the climbing shoes as a pair, Norwegian would often use:

• klatreskoene = the climbing shoes

So a learner might expect:

• kalkposen og klatreskoene

That said, the sentence you were given uses the singular form, so grammatically it means the climbing shoe. If the intended meaning shown to you is broader, that may just reflect context or the exercise’s wording, but strictly speaking the form here is singular.

Here are the indefinite singular forms:

• en buldreøkt = a bouldering session
• en kalkpose = a chalk bag
• en klatresko = a climbing shoe
• en landingsmatte = a landing mat

And the definite forms used in the sentence are:

• buldreøkten = the bouldering session
• kalkposen = the chalk bag
• klatreskoen = the climbing shoe
• landingsmatten = the landing mat

This is a very useful pattern to memorize:

• en X → X-en

for many common-gender nouns.