Vi følger sorteringsguiden, folder papkassen sammen og sparer plads.

Because all three verbs share the same subject: vi = we.

So the sentence works like this:

• Vi følger sorteringsguiden
• (vi) folder papkassen sammen
• (vi) sparer plads

In Danish, just like in English, you do not need to repeat the subject if it stays the same in a coordinated list of actions.

They are all in the present tense.

In Danish, the present tense is often formed with -r or -er, depending on the verb:

• at følge → følger
• at folde → folder
• at spare → sparer

So this sentence is describing something happening now, or something that is generally done: we follow..., fold..., and save...

Sorteringsguiden is a compound noun:

• sortering = sorting
• guide = guide
• sorteringsguide = sorting guide
• sorteringsguiden = the sorting guide

A few useful points:

1. Danish very often joins nouns into one word.
2. The -s- in sorterings- is a linking element that often appears in compounds.
3. The ending -en makes the noun definite: the guide.

So sorteringsguiden literally means the sorting guide.

Again, this is a compound noun:

• pap = cardboard
• kasse = box
• papkasse = cardboard box
• papkassen = the cardboard box

Danish usually writes compound nouns as one word, where English often uses two words.

The ending -en is the definite article attached to the noun. Instead of a separate word like English the, Danish often adds it to the end:

• en papkasse = a cardboard box
• papkassen = the cardboard box

Here sammen means something like together, up, or flat, depending on context.

The expression at folde sammen means to fold up, to fold together, or in this kind of practical context, to flatten/fold down something.

So:

• folde = fold
• folde sammen = fold up / fold flat / collapse by folding

In this sentence, folder papkassen sammen means folding the cardboard box so it takes up less room.

Because with this kind of verb + particle expression, Danish often places the object between the verb and the particle.

So:

• at folde noget sammen = to fold something up

In a normal sentence, that becomes:

• Vi folder papkassen sammen

This is very natural Danish word order.
English does something similar with phrasal verbs:

• We fold the box up

So papkassen sits between folder and sammen much like the box sits between fold and up in English.

Because plads is used here in a general, uncountable sense: space.

The expression at spare plads means to save space.
You do not need an article here, just as in English you normally say save space, not save a space.

Compare:

• Vi sparer plads = We save space
• Der er ikke plads = There is no room / space

So plads here is a general concept, not one specific space.

It can mean both, depending on context.

• følge en person = follow a person
• følge en guide / en regel / en instruktion = follow a guide / rule / instruction

In this sentence, følger sorteringsguiden means follow the sorting guide, in the sense of using its instructions or doing what it says.

So it is not about walking behind the guide; it is about following guidance.

It separates the first action from the next ones in a series:

• følger sorteringsguiden
• folder papkassen sammen
• sparer plads

So the sentence lists three related actions done by the same subject, vi.

In practice, this comma helps readability by breaking up the list. The main idea is that the sentence contains a sequence of coordinated actions: we follow..., fold..., and save...

Yes. Structurally, that is very close to the Danish.

A very literal breakdown is:

• Vi = we
• følger sorteringsguiden = follow the sorting guide
• folder papkassen sammen = fold the cardboard box up / flat
• og sparer plads = and save space

That makes this sentence a good example of how Danish can line up quite closely with English, while still having its own features such as:

• compound nouns: sorteringsguiden, papkassen
• definite endings: -en
• verb-particle placement: folder ... sammen