Learn Hardcore Norwegian: Studenten leser boken om prosjektet. - The student reads the book about the project.

In Bokmål, adding -en to a common (masculine/feminine) noun makes it definite singular. So student (“a student”) becomes studenten (“the student”).

Why is boken also in the definite form? Could I say bok or boka instead?

Here boken means “the book” (a specific one).

bok (indefinite) = “a book”
boken = “the book” (formal/written style)
boka = “the book” (colloquial/spoken style)
All three are correct, but only boken and boka are definite.

How do I know to use leser as the verb form?

Norwegian verbs aren’t marked for person. The infinitive is lese (“to read”). In present tense you add -er, giving leser. It works for all subjects:

jeg leser, du leser, han leser, vi leser, osv.

What does om mean in boken om prosjektet?

om is a preposition meaning “about” or “concerning.” So boken om prosjektet literally means “the book about the project.”

Why is prosjektet definite with “-et”?

prosjekt is a neuter noun. Adding -et makes it definite singular (prosjektet = “the project”). Without -et, prosjekt would mean “a project,” which isn’t as specific.

What is the word order in this sentence?

It follows the standard SVO pattern plus a prepositional phrase:
Subject (Studenten) + Verb (leser) + Object (boken) + Prepositional phrase (om prosjektet).

How would the meaning change if I made everything indefinite?

You’d say: En student leser en bok om et prosjekt.
That becomes “A student is reading a book about a project,” referring to any student, any book, any project—not specific ones.