Á morgun fer ég til tannlæknis, þar sem ég finn til.

Because the first part is a main clause, and Icelandic is usually a V2 language. That means the finite verb normally comes in the second position.

So when Á morgun is placed first, the verb fer must come next: Á morgun fer ég ...

In the second part, þar sem introduces a subordinate clause. In subordinate clauses, Icelandic normally uses regular subject + verb order: þar sem ég finn til

So this contrast is completely normal:

• main clause: Á morgun fer ég
• subordinate clause: þar sem ég finn til

Yes. Fer is present tense, but Icelandic often uses the present tense to talk about the future when the time is already clear from the context.

Here, Á morgun makes the time reference future, so fer is naturally understood as am going / will go.

This is similar to English sentences like:

• Tomorrow I’m going to the dentist
• I leave tomorrow

So Icelandic does not need a special future form here.

Fer is from the verb fara, which means to go.

This is an irregular verb, so the form changes quite a bit:

• að fara = to go
• ég fer = I go / I am going

That difference can look surprising at first, but it is very common in Icelandic strong verbs.

Á morgun is a fixed Icelandic expression meaning tomorrow.

The preposition á is just part of the idiom here. You should learn á morgun as a whole phrase rather than trying to translate it word-for-word.

So:

• á morgun = tomorrow

This is one of those expressions where Icelandic and English simply package time differently.

Because the preposition til takes the genitive case.

The dictionary form is:

• tannlæknir = dentist

After til, it changes to the genitive singular:

• til tannlæknis

So this is a case change caused by the preposition.

Icelandic often leaves out the article in expressions like fara til tannlæknis.

So til tannlæknis can naturally mean something like:

• to the dentist
• to a dentist

The exact nuance depends on context.

If you wanted to be more explicitly definite, you could say:

• til tannlæknisins = to the dentist / to the particular dentist

But in everyday Icelandic, fara til tannlæknis is a very normal way to say go to the dentist.

Þar sem can mean different things depending on context.

It can mean where, but in this sentence it means because or since.

So here it introduces the reason:

• þar sem ég finn til = because I am in pain / since I am feeling pain

This is a very common use of þar sem in Icelandic.

Yes, it is related to finna, but finna til is an idiomatic expression. It does not mean find to.

In this sentence, að finna til means:

• to feel pain
• to be sore
• to ache
• to be hurting

So ég finn til means something like I’m in pain or something hurts.

This is a good example of why it is important to learn some Icelandic verbs together with their particles or prepositions.

It can definitely stand by itself.

Ég finn til is a natural sentence meaning that you are feeling pain or discomfort, even if you do not specify where.

If you want to say what hurts, you can add it:

• Ég finn til í tönninni. = I have pain in my tooth.
• Ég finn til í bakinu. = My back hurts / I have pain in my back.

So in your sentence, leaving it general is perfectly normal.

Because þar sem ég finn til is a subordinate clause, and Icelandic often uses commas to separate subordinate clauses from the main clause.

So the comma helps show the structure:

• Á morgun fer ég til tannlæknis
• þar sem ég finn til

Icelandic punctuation often marks clause boundaries a bit more clearly than English does.

Þ is pronounced like the th in thing, not like the th in this.

So:

• þar begins with the same sound as think

A rough learner-friendly pronunciation of þar sem would be:

• thar sem

Also useful here:

• á is pronounced roughly like ow in now
• ég is roughly like yeg
• fer is roughly like fer
• til is roughly like til
• tannlæknis is roughly tan-lyke-nis

Those English-style approximations are not perfect, but they can help you get started.