Learn Farsi: کتابت را روی میز بگذار.

It is the singular command for "put." You make it by adding the imperative prefix be- to the present stem -gozār- (from the verb gozāshtan). Because the stem has an "o" sound in conversational Farsi, the prefix usually changes pronunciation to bo-, making the whole word bogzār.

Where is the word for "your" in ketābat?

In Farsi, possession is often shown by attaching a short suffix directly to the noun. Here, -at is the suffix for "your" (singular). So, ketāb (book) + -at becomes ketābat (your book).

Why is the word rā used right after ketābat?

rā is a marker that points out the specific direct object of a sentence (the thing receiving the action). Because the command is about a specific book ("your book" rather than just "a book"), Farsi requires rā immediately after it.

How do the words ruy and miz connect to mean "on the table"?

ruy means "on" or "surface." When a preposition like this is followed by a noun, they are connected by the invisible ezafe vowel (an "e" sound). You do not see it written in the Persian script here, but you pronounce the phrase as ruy-e miz.