Ef það verður mögulegt, komum við snemma; annars verður næstum ómögulegt að finna laust borð.

Because Icelandic main clauses normally follow the V2 rule: the finite verb comes in the second position.

In this sentence, the whole if-clause — Ef það verður mögulegt — takes the first position. That means the finite verb of the main clause must come next:

Ef það verður mögulegt, komum við snemma.

So:

• Ef það verður mögulegt = subordinate clause first
• komum = finite verb in second position
• við = subject after the verb

If the sentence started directly with the subject, you would get:

Við komum snemma ef það verður mögulegt.

Because subordinate clauses introduced by ef do not normally use main-clause V2 word order.

So inside the ef-clause, you get the more regular order:

• ef það verður mögulegt = if it becomes / is possible

That gives a useful contrast:

• subordinate clause: það verður
• main clause after fronting: komum við

Yes, komum is a present-tense form of koma.

Icelandic often uses the present tense to refer to the future when the context makes the future meaning clear. English does this sometimes too, but Icelandic does it very naturally.

So:

• komum við snemma literally = we come early
• in context = we’ll come early

Literally, verður mögulegt means becomes possible.

In natural English, depending on context, it is often best translated as:

• will be possible
• turns out to be possible
• becomes possible

So Ef það verður mögulegt is very close to:

• If it becomes possible
• or more naturally, If it’s possible / If it will be possible

Here það is a dummy subject, like English it in if it is possible.

It does not refer to a specific object. It is just there because Icelandic, like English, often uses a formal subject in expressions such as:

• það er mögulegt = it is possible
• það er erfitt = it is difficult

So in this sentence, það is grammatical, not really meaningful by itself.

Because Icelandic often leaves out the dummy það in this kind of impersonal adjective + infinitive structure.

The real idea is carried by the infinitive phrase:

• að finna laust borð = to find a free table

So the sentence means:

• otherwise, [it will be] almost impossible to find a free table

You can also sometimes see það included:

• Annars verður það næstum ómögulegt að finna laust borð.

But the version without það is very natural.

Because they are neuter singular adjective forms.

That happens here because the adjective is used:

• with dummy það, which is neuter
• or with a whole clause/infinitive idea as the subject, which also commonly takes neuter singular

So:

• mögulegur = possible
• mögulegt = neuter singular form
• ómögulegt = impossible / not possible

The prefix ó- often means un- / im- / in-.

Annars means otherwise or if not here.

It connects the second clause to the first:

• Ef það verður mögulegt, komum við snemma
• annars = otherwise
• verður næstum ómögulegt...

So it means: if the first condition is not met, the second result follows.

It literally means to find a free table.

Breaking it down:

• að finna = to find
• laust = free, vacant, available
• borð = table

In this context, laust borð means an unoccupied / available table, not a table that is physically loose.

It is the direct object of finna, so it is in the accusative.

However, with a neuter singular noun like borð, the nominative and accusative look the same, so the form does not visibly change.

The adjective agrees with the noun:

• laust = neuter singular
• borð = neuter singular noun

So even though you do not see a different ending here, grammatically it is the object of finna.

Næstum is an adverb meaning almost or nearly.

It modifies the adjective ómögulegt:

• næstum ómögulegt = almost impossible

So the sentence is not saying it is fully impossible, but very nearly so.

Yes, and the difference is small but real.

• Ef það er mögulegt = If it is possible
• Ef það verður mögulegt = If it becomes / turns out to be possible

Using verður can suggest that the possibility depends on how things develop. It feels a little more dynamic or situation-dependent.