Lægen lagde en ren forbinding og sagde, at salven kun skal bruges to gange om dagen.

Because they are in the definite singular form:

• en læge = a doctor
• lægen = the doctor
• en salve = an ointment
• salven = the ointment

Many common-gender Danish nouns that end in an unstressed -e form the definite singular by adding -n:

• læge → lægen
• salve → salven

So the sentence is talking about a specific doctor and a specific ointment.

Lagde is the past tense of lægge.

• lægge = to lay, put, place
• lagde = laid / put / placed

In medical Danish, lægge en forbinding means to put on / apply a dressing or bandage.

So Lægen lagde en ren forbinding means the doctor applied a clean dressing.

Because Danish adjectives agree with the noun.

Forbinding is a common-gender noun (en forbinding), and here it is:

• singular
• indefinite
• common gender

So the adjective takes the common singular indefinite form:

• en ren forbinding = a clean dressing

Compare:

• et rent sår = a clean wound (neuter)
• rene forbindinger = clean dressings (plural)
• den rene forbinding = the clean dressing (definite)

Forbinding usually means a dressing or bandage, especially in a medical context.

It can refer to the material placed on a wound to protect it. In English, the best translation depends on context:

• dressing
• bandage
• sometimes wound dressing

In this sentence, forbinding most naturally means a clean dressing/bandage.

Here at means that and introduces a subordinate clause:

• sagde, at ... = said that ...

So:

• Lægen ... sagde, at salven kun skal bruges ...
• The doctor ... said that the ointment should/is to be used only ...

This is standard indirect speech in Danish.

It marks the start of the subordinate clause after sagde.

So the sentence is divided like this:

• main clause: Lægen lagde en ren forbinding og sagde
• subordinate clause: at salven kun skal bruges to gange om dagen

A useful thing to know: in modern Danish, the comma before a subordinate clause like this is often optional, depending on the comma style being used. So both of these can be acceptable:

• ... sagde, at salven ...
• ... sagde at salven ...

Because after at, Danish uses subordinate clause word order.

In a main clause, Danish normally has verb-second word order:

• Salven skal kun bruges to gange om dagen.

But in a subordinate clause introduced by at, the finite verb does not stay in second position. Adverbs like kun often come before the finite verb:

• at salven kun skal bruges ...

That is why the order is:

• salven = subject
• kun = adverb
• skal = finite verb
• bruges = infinitive passive

Because Danish often keeps the tense that matches the real meaning, rather than automatically shifting it back after a past reporting verb.

Here the doctor’s instruction is still valid now, so skal is natural:

• sagde, at salven kun skal bruges ...
• said that the ointment is only to be used ...

If you used skulle, it could sound more like you are viewing the instruction purely from the past, or reporting it with more distance.

So:

• skal = the instruction still applies
• skulle = more backshifted/past perspective

English often backshifts more than Danish does, so this is a very common thing for learners to notice.

This is a passive construction.

• bruge = to use
• bruges = be used

So:

• man skal bruge salven = one/you must use the ointment
• salven skal bruges = the ointment must be used

The Danish -s passive is very common. Here it shifts the focus from the person using the ointment to the ointment itself.

In this subordinate clause, kun is placed before the finite verb because of normal Danish subordinate-clause word order.

It also shows what is being limited: the ointment is to be used only twice a day.

So:

• at salven kun skal bruges to gange om dagen

is the natural Danish way to say that the use is limited to that frequency.

If you place kun elsewhere, the sentence can sound less natural or slightly change the emphasis.

This is a fixed and very common way to express frequency in Danish:

• én gang om dagen = once a day
• to gange om dagen = twice a day
• tre gange om dagen = three times a day

A few details:

• gang means time/occurrence
• after to, it becomes plural: gange
• om dagen is the idiomatic way to say a day / per day

So although it literally looks a bit like about the day, the expression simply means per day or a day.

You can also see similar patterns like:

• to gange om ugen = twice a week
• fire gange om året = four times a year