Send mig en besked når som helst i weekenden, hvis du finder en bedre løsning.

Send is the imperative form, used for commands or instructions.

• Send mig en besked = Send me a message
• Du sender mig en besked = You are sending me a message / You send me a message

So the sentence is giving an instruction, not describing an action.

Because mig is the object form of the pronoun, while jeg is the subject form.

• jeg = I
• mig = me

In Send mig en besked, the person receiving the action is me, so Danish uses mig, just as English uses me rather than I.

In normal Danish, sende en besked is the standard expression for send a message.

So:

• en besked = a message
• send mig en besked = send me a message

You may sometimes see send besked in apps, buttons, headlines, or very short informal writing, but in a full sentence send mig en besked sounds more natural and complete.

Når som helst is a fixed expression meaning any time, whenever, or at any point.

So:

• når som helst i weekenden = any time during the weekend

Even though når often means when, in this expression the whole phrase should be learned together as når som helst.

They do different jobs here.

• når som helst is part of the fixed phrase meaning any time
• hvis introduces the condition: if you find a better solution

So:

• når som helst i weekenden = time phrase
• hvis du finder en bedre løsning = conditional clause

A useful rule is:

• hvis = if
• når = usually when, but sometimes part of set expressions like når som helst

In Danish, i weekenden is the normal way to say at/on the weekend.

This is just the standard preposition used with this time expression:

• i weekenden = this/the weekend
• om weekenden = on weekends / during the weekend regularly

So in your sentence, i weekenden refers to a specific upcoming weekend, not weekends in general.

The ending -en is the definite article attached to the noun.

• en weekend = a weekend
• weekenden = the weekend

Danish often uses the definite form in time expressions where English may also say the or sometimes just use a set phrase naturally:

• i weekenden = at the weekend / this weekend

So the -en is completely normal here.

Danish often uses the present tense for future meaning, especially after words like hvis.

So:

• hvis du finder en bedre løsning literally uses present tense
• but it means if you find / if you happen to find a better solution

This is very similar to English, which also says if you find, not usually if you will find.

Bedre is the comparative form of god.

• god = good
• bedre = better
• bedst = best

This is an irregular pattern, just like English good → better → best.

So:

• en bedre løsning = a better solution

Because hvis introduces a subordinate clause, and subordinate clauses in Danish do not use the normal main-clause verb-second word order.

Compare:

• Main clause: Du finder en bedre løsning
• Subordinate clause: hvis du finder en bedre løsning

So after hvis, the subject du comes before the verb finder.

This is an important pattern in Danish:

• main clauses often have verb-second order
• subordinate clauses usually do not

It depends on which comma system is being used in Danish.

The sentence has:

• ..., hvis du finder en bedre løsning.

That comma is common and correct in the traditional grammatical comma system, where a comma is placed before subordinate clauses.

In modern Danish, you may also see sentences written without that comma, depending on style and rules being followed.

So the comma here is normal, but you may encounter both versions.