Vores cykler står ved siden af hinanden.

Because Danish often uses verbs like stå, ligge, and sidde to describe how something is positioned, not just that it exists somewhere.

In this sentence, står is natural because bikes are understood as being upright / standing.

• Cyklerne står udenfor. = The bikes are outside.
• Bogen ligger på bordet. = The book is on the table.

You can sometimes hear er in similar situations, but står sounds more natural when talking about bicycles that are parked or standing upright.

Ved siden af means next to or beside.

It is a fixed expression:

• ved = by / at
• siden = side
• af = of

So literally it is something like by the side of, but in normal English you would translate it as next to.

Examples:

• Hun sidder ved siden af mig. = She is sitting next to me.
• Huset ligger ved siden af skolen. = The house is next to the school.

Because ved siden af is just the normal Danish expression. You usually learn it as a whole phrase.

Danish often uses multi-word prepositions where English uses one word:

• ved siden af = next to
• på grund af = because of
• i stedet for = instead of

So it is best to remember ved siden af as one complete unit.

Hinanden means each other or one another.

It is used when two or more people or things do something mutually or are in a mutual relationship.

In this sentence:

• ved siden af hinanden = next to each other

More examples:

• De elsker hinanden. = They love each other.
• Vi hjælper hinanden. = We help each other.

So hinanden does not refer to one specific noun by itself; it expresses a reciprocal relationship.

In Danish, a possessive like vores normally comes directly before the noun, just like our in English.

So:

• vores cykel = our bike
• vores cykler = our bikes

You do not add an article like de in front.

This is similar to English:

• our bikes ✅
• the our bikes ❌

Cykler is the plural indefinite form of cykel.

The forms are:

• en cykel = a bike
• cyklen = the bike
• cykler = bikes
• cyklerne = the bikes

So in vores cykler, Danish uses the plain plural form cykler because the possessive vores already makes it definite in meaning: our bikes.

Yes, people would understand it, and it is not grammatically wrong. But står is usually more idiomatic here.

The difference is roughly:

• står = focuses on the bikes’ physical position as upright objects
• er = more neutral, just says they are there

With bicycles, Danish often prefers står.

Yes: it follows normal Danish main-clause word order.

• Vores cykler = subject
• står = verb
• ved siden af hinanden = adverbial/prepositional phrase

So the basic structure is:

Subject + verb + other information

This is a normal statement pattern in Danish.

If you move something else to the front, Danish usually keeps the verb in second position:

• Ved siden af hinanden står vores cykler.

That version is possible, but it sounds more marked or literary. The original sentence is the most natural everyday order.

It can be used for two or more.

So hinanden works for:

• two bikes next to each other
• three people helping each other
• several houses standing next to each other

In your sentence, since cykler is plural, hinanden simply means the bikes are next to one another.

Then you would not use hinanden, because hinanden requires a mutual relationship.

You would say:

• Min cykel står ved siden af bilen. = My bike is next to the car.

Use hinanden only when the things are next to each other, not when one thing is next to a different object.