Learn Farsi: خواندن یک کتاب جدید زیبا است.

You can spot a Farsi infinitive because it always ends in -dan or -tan. Here, خواندن ends in -dan. To use this verb in the present tense later on, you need its present stem. For this verb, the present stem is خوان which you will need to memorize, as present stems are often irregular.

Why does the sentence use the infinitive خواندن to mean "reading"?

In English, we add "-ing" to make a verb act like a noun (a gerund), like "reading". In Farsi, you just use the full infinitive! So خواندن serves as both "to read" and the noun "reading" at the beginning of this sentence.

How do the words for "book" and "new" connect in کتاب جدید?

They are connected by the Ezafe, which is a short "eh" sound added to the end of the noun. Farsi adjectives come after the noun, so the invisible Ezafe links them together to sound like "ketaab-e jadid".

Why does the sentence end with است?

Farsi sentences usually follow a Subject-Object-Verb word order, meaning the main verb almost always goes at the very end. Here, the verb is است meaning "is", so it naturally sits at the end of the sentence.