Learn Farsi: آنان دانشجوی ایرانی‌اند.

آنان is a plural demonstrative used specifically for people. It has a slightly more formal or literary feel. آن‌ها is more common in everyday speech and can be used for both people and objects.

If "those people" is plural, why is the word for student (دانشجو) singular in Farsi?

In Farsi, when you state the profession or identity of a group, the noun describing them usually stays in the singular form. The plural verb at the end of the sentence is enough to show that you are talking about multiple people.

Why is there a ی (ye) attached to دانشجو (student) to make دانشجوی?

This is the ezâfe, a hidden grammatical link used to connect a noun to its adjective (student + Iranian). Because دانشجو ends in a long vowel sound (u), we need a consonant bridge before adding the ezâfe vowel "e". The ی acts as this bridge, so it is pronounced dâneshju-ye.

What is the اند attached to the end of ایرانی (Iranian)?

That is the short, attached form of the verb "to be" for the "they" form. Instead of using a separate, full word for "are" (like هستند), Farsi often attaches these short endings directly to the adjective or noun. Here, ایرانی plus اند means "they are Iranian."