Hún sagði að hún hefði beðið í sextíu mínútur eftir húsvörðinum í anddyrinu.

Here að means that and introduces a subordinate clause:

Hún sagði að ... = She said that ...

This is different from the infinitive marker að in phrases like að lesa (to read). Icelandic uses the same word for both functions, so context tells you which one it is.

Because there are two clauses, and each clause has its own subject:

• Hún sagði = She said
• að hún hefði beðið ... = that she had waited ...

Icelandic normally states the subject again in the subordinate clause. English does the same here.

Hefði beðið is a very common choice in reported speech after a past verb like sagði.

• hefði = past subjunctive of hafa
• beðið = the form used with hafa to make a compound tense

So hefði beðið is roughly had waited here.

Why subjunctive? Because the speaker is reporting what someone said, rather than presenting it directly as their own plain statement of fact. In Icelandic, that often leads to the subjunctive in the að-clause.

In some contexts, hafði beðið could also appear, but hefði beðið is very natural for indirect/reported speech.

Not in this sentence.

Although hefði can sometimes translate as would have, here it is part of reported speech and is best understood as had rather than would have.

So here:

• hún hefði beðið = she had waited

not

• she would have waited

Context is what tells you which meaning is intended.

Beðið is the non-finite form of bíða (to wait) used after hafa.

Compare:

• hún beið = she waited
• hún hefur beðið = she has waited
• hún hefði beðið = she had waited / she was said to have waited

So beið is the simple past form, while beðið is the form used in compound tenses.

Yes. Beðið can also be a form of biðja (to ask, to request, sometimes to pray).

But here it must be from bíða (to wait) because of the structure and meaning, especially:

• bíða eftir einhverjum = wait for someone

So in this sentence, beðið is understood as waited, not asked.

This means for sixty minutes, expressing duration of time.

The phrase uses the accusative:

• í sextíu mínútur

Even though mínútur looks the same as the nominative plural, here it functions as accusative plural.

This is a common Icelandic pattern for duration:

• í tvo daga = for two days
• í eina viku = for one week
• í sextíu mínútur = for sixty minutes

This í is not really about physical location here; it is part of a time expression.

Because Icelandic usually says bíða eftir einhverjum for wait for someone.

The preposition eftir here governs the dative, so the noun after it must be in the dative case:

• dictionary form: húsvörður
• dative singular definite: húsvörðinum

So:

• eftir húsvörðinum = for the janitor

This is something English speakers often just have to memorize as part of the verb pattern:

• bíða eftir + dative

It shows two things at once:

• dative singular
• definite (the janitor)

The base noun is húsvörður.

Very roughly:

• húsvörður = a janitor / the janitor as subject form
• húsvörðinum = to/for/after the janitor in dative singular, depending on the preposition or verb pattern

So the ending is doing grammatical work that English usually expresses with word order or separate words.

Because this phrase gives a location, not movement.

With í:

• dative = location (in)
• accusative = movement into (into)

So:

• í anddyrinu = in the lobby
• í anddyrið = into the lobby

Here she was waiting in the lobby, so the dative is required.

It is dative singular definite.

The noun is anddyri (lobby, entrance hall), which is a neuter noun. After í with location, it goes into the dative:

• anddyri = base form
• anddyrinu = in the lobby / the lobby in dative singular definite

Most naturally, it describes where she waited:

• She waited in the lobby for the janitor.

That is the default reading most learners should take from this sentence.

In theory, the phrase could be interpreted differently in some contexts, but if you specifically wanted to say the janitor who was in the lobby, Icelandic would usually make that clearer with a different structure, for example:

• ... eftir húsvörðinum sem var í anddyrinu
  = ... for the janitor who was in the lobby

Some parts can move, but the given order is very natural.

In the subordinate clause, the finite verb typically comes early:

• að hún hefði beðið ...

Then other elements such as time, object of the preposition, and location can sometimes be rearranged for emphasis or style.

For example, Icelandic can be somewhat flexible with adverbials, but the version you have is a good neutral model to learn from:

• að hún hefði beðið í sextíu mínútur eftir húsvörðinum í anddyrinu

So yes, some movement is possible, but this sentence has standard, learner-friendly word order.