We use “את”  to show when we’re talking about something specific in Hebrew. Like rather than אני קורה ספר” (“I’m reading a book” ” ) I could say  אני קורה את  הספר”( “I’m reading the book””), just be sure to put a ה before the noun your talking about. Unless its a proper noun. Then you would say אני קורה את הרי פתר” (“I’m reading Harry potter””).