Jeg lægger mine bøger i min rygsæk, før jeg går til universitetet.

Because at lægge and at ligge are different verbs.

• at lægge = to lay / put / place something
• at ligge = to lie / be lying / be located

In this sentence, the speaker is doing something to the books, so Danish uses lægger:

• Jeg lægger mine bøger ... = I put my books ...

If you wanted to describe where the books already are, you would use ligger:

• Mine bøger ligger i min rygsæk = My books are in my backpack

This is a very common Danish verb pair, and English speakers often confuse it.

Because Danish possessive words must agree with the noun they belong to.

Here is the basic pattern for my:

• min for a singular common gender noun
• mit for a singular neuter noun
• mine for plural nouns

So:

• min rygsæk because rygsæk is singular and common gender
• mine bøger because bøger is plural

More examples:

• min bil = my car
• mit hus = my house
• mine sko = my shoes

In Danish, a possessive like min, mit, mine, din, hans, vores usually takes the place of an article.

So you say:

• min rygsæk not den min rygsæk
• mine bøger not de mine bøger

This is similar to English, where we say my backpack, not the my backpack.

Because i means in / inside, and a backpack is treated as a container.

So:

• i min rygsæk = in my backpack

This is very natural in Danish. If something is inside a bag, box, room, drawer, and so on, i is often the right choice.

Examples:

• i tasken = in the bag
• i skabet = in the cupboard
• i bilen = in the car

Not necessarily. In Danish, gå can mean go, not only walk.

So jeg går til universitetet can simply mean I go to the university. It does not have to emphasize that the person is walking there.

Danish often uses gå in a broader way than English learners expect. Context tells you whether it means literal walking or just going somewhere.

This is an important difference.

• gå til universitetet = go to the university
  This is about movement toward the place.
• gå på universitetet = attend / study at university
  This is about being a student there.

So in your sentence, går til universitetet focuses on going there, not on enrollment status.

Compare:

• Jeg går til universitetet klokken otte = I go to the university at eight
• Jeg går på universitetet = I am a university student / I attend university

Because Danish usually adds the definite article to the end of the noun.

So:

• et universitet = a university
• universitetet = the university

That -et is the definite ending for a neuter noun.

In this sentence, Danish uses the definite form universitetet. That often happens when the place is understood in context as a specific one, such as the university the speaker normally goes to.

Because Danish, like English, often uses the present tense for:

• habits
• routines
• scheduled actions
• near-future actions

So Jeg lægger mine bøger i min rygsæk, før jeg går til universitetet can mean something like a regular routine: I put my books in my backpack before I go to the university.

This is completely normal Danish.

After før, you get a subordinate clause.

In the sentence:

• før jeg går til universitetet

the order is:

• før
  • subject
    • verb

So it stays jeg går, not går jeg.

This is different from main-clause inversion in Danish. For example:

• Nu går jeg til universitetet = Now I go to the university

Here, går jeg appears because Nu is in first position in a main clause. But after før, the clause is subordinate, so the normal order is jeg går.

It depends on the comma system being used.

In Danish, you may see both:

• Jeg lægger mine bøger i min rygsæk, før jeg går til universitetet.
• Jeg lægger mine bøger i min rygsæk før jeg går til universitetet.

Many learners are taught to include the comma before a subordinate clause, and that is very common. But modern Danish punctuation allows variation depending on the chosen comma style.

So the comma here is normal, and you will often see it, but you may also see the sentence without it.