Hvis jeg får tid, går jeg til biblioteket.

This is because of the V2 rule in Norwegian main clauses: the finite verb normally comes in the second position.

In this sentence, the whole clause Hvis jeg får tid takes the first position. That means the verb of the main clause must come next:

• Hvis jeg får tid, går jeg til biblioteket.

If you start with the subject instead, then you get the more basic order:

• Jeg går til biblioteket hvis jeg får tid.

So the inversion happens because the sentence starts with something other than the subject.

Norwegian very often uses the present tense to talk about the future when the context already makes the future meaning clear.

That is especially common in:

• if-clauses
• schedules
• plans
• likely future actions

So:

• Hvis jeg får tid, går jeg til biblioteket.

is a very natural way to say what English often expresses as If I have time, I'll go to the library.

Norwegian could also use a future-style form, for example:

• Hvis jeg får tid, skal jeg gå til biblioteket.

But the simple present is completely normal and often the most natural choice.

Literally, får tid means get time. But in natural English, it is often best understood as:

• have time
• find time
• get the chance

So Hvis jeg får tid does not always mean time is physically given to you. It usually means if time becomes available or if I can make time.

Compare:

• Jeg har tid. = I have time.
• Jeg får tid senere. = I’ll have time later / I’ll get some time later.

In your sentence, får tid suggests that the speaker may or may not end up having enough free time.

Hvis is the most common and straightforward word for if in a conditional sentence like this one.

• Hvis jeg får tid, går jeg til biblioteket.

You may sometimes hear om used in similar situations, but for learners, hvis is the safest choice for ordinary if conditions.

A few rough guidelines:

• hvis = if
• om often = whether, about, in/after, depending on context

So if you want to express a clear condition, hvis is usually the best word.

You might also see:

• dersom = if, but more formal or written

In Norwegian, it is standard to put a comma after a subordinate clause when it comes before the main clause.

So:

• Hvis jeg får tid, går jeg til biblioteket.

The first part, Hvis jeg får tid, is the subordinate clause. The second part, går jeg til biblioteket, is the main clause.

If you put the main clause first, you would usually write:

• Jeg går til biblioteket hvis jeg får tid.

So the comma is connected to the sentence structure, not just to a pause in speech.

It is a subordinate clause introduced by the conjunction hvis.

A useful thing to notice is that subordinate clauses in Norwegian usually keep the normal subject-verb order:

• hvis jeg får tid

Also, negation helps show the difference between subordinate and main clauses:

• Main clause: Jeg får ikke tid.
• Subordinate clause: hvis jeg ikke får tid

In subordinate clauses, words like ikke usually come before the finite verb if the verb is not already in a special position. This is one of the important word-order patterns Norwegian learners need to get used to.

Til means to, so gå til biblioteket means go to the library.

• til biblioteket = to the library

Without til, the sentence would not work properly with gå in this meaning.

This is a very common pattern:

• gå til skolen = go to school
• gå til butikken = go to the shop/store
• gå til legen = go to the doctor

So here, til is the preposition that marks movement toward a place.

Biblioteket is the definite form and means the library.

In Norwegian, the definite article is usually attached to the end of the noun:

• et bibliotek = a library
• biblioteket = the library

So instead of having a separate word like the, Norwegian often adds an ending.

In this sentence, the speaker is talking about the library in a general familiar sense, just as English often says go to the library rather than go to a library.

Yes, absolutely.

That version is also correct:

• Hvis jeg får tid, skal jeg gå til biblioteket.

The difference is mainly one of tone and emphasis:

• går jeg til biblioteket = very natural, neutral, common
• skal jeg gå til biblioteket = a bit more clearly future-oriented, often sounding more like a plan or intention

Both are good Norwegian. The version with the simple present is often the more idiomatic everyday choice.

Only if you want a different meaning.

• hvis = if
• når = when

So:

• Hvis jeg får tid, går jeg til biblioteket. = It may or may not happen.
• Når jeg får tid, går jeg til biblioteket. = I expect it to happen; the question is when, not whether.

This is an important distinction. English sometimes uses if where Norwegian may prefer when, but in your sentence hvis clearly expresses a condition.

Literally, gå often means walk, but in many everyday sentences it can also correspond to English go, especially when the exact method of movement is not the main point.

So in this sentence, går jeg til biblioteket can naturally be understood as going to the library, often with the sense of walking there.

If you wanted to avoid the idea of walking, you could use another verb, depending on context:

• drar jeg til biblioteket = I go / head to the library
• reiser jeg til biblioteket = I travel to the library

But the original sentence is perfectly normal.

Yes, and that is also very natural.

Both are correct:

• Hvis jeg får tid, går jeg til biblioteket.
• Jeg går til biblioteket hvis jeg får tid.

The difference is mainly focus:

• Starting with Hvis jeg får tid puts attention on the condition.
• Starting with Jeg går til biblioteket puts attention on the action.

Also notice the word order change:

• after fronting the subordinate clause: går jeg
• without fronting it: jeg går

That is a very common Norwegian pattern.