Doubt in the FOR command

Question

Good afternoon, I am a beginner in C# (it is not even 2 days since I started studying) and I would like an explanation of the line:

WriteLine($"{n1:d2} x {n2:d2} = {n1 * n2:d2}");

Relating to that code:

using static System.Console;

public class Program {
    public static void Main() {
        for (int n1 = 1; n1 < 11; n1++) {
            for (int n2 = 1; n2 < 11; n2++){
                WriteLine($"{n1:d2} x {n2:d2} = {n1 * n2:d2}");
            }
            WriteLine();
        }
    }
}

If you can send me a video that teaches how to use Writeline this way, thank you rsrs! Because I don’t understand the logic of $ and of {}.