Using Recursive Functions in VB.net - vb.net

Question

I found this piece of code in MSDN documentation as an example of recursive functions: The link is provided below:
https://learn.microsoft.com/en-us/dotnet/visual-basic/programming-guide/language-features/procedures/recursive-procedures
Function Factorial(n As Integer) As Integer ......'statement 1
If n <= 1 Then
Return 1
End If
**Return Factorial(n - 1) * n** 'Statement II: Not understanding how this helps calculating the factorial
End Function
Although I do understand how recursive functions work, I do not understand how statement II is calculating the factorial. For example say we enter n =5, in the first step. Then as per my understanding the first part of the statement II Return **Factorial(n - 1)** shall call the Factorial function in statement I and send the parameter n-1 = 4. And this is where my first question is: When we are calling Factorial function in statement I from statement II and passing the parameter (n-1) which equals 4 we are also multiplying it by n....what exactly are we returning in statement II...? In other words can someone explain in a step by step manner how the factorial value is getting calculated?
Also i tried using this piece of code to write a full program but unfortunately i could not make it work. To make it work I had to introduce a second parameter in the Factorial function - a parameter that would actually store the calculated value. I have provided the code below. My second question is: Is it possible to simplify the code I have written...the idea is not to use the second parameter "fact"...Is that possible?
The code that I wrote is as follows:
Module Module1
Sub Main()
Dim number As Integer
Dim fact As Integer = 1
Console.Write("Please enter number: ")
number = Console.ReadLine()
Factorial(number, fact)
Console.ReadLine()
End Sub
Function Factorial(ByVal n As Integer, ByVal fact As Integer) As Integer
If n > 0 Then
Console.WriteLine("Current Value of n = {0}", n)
End If
If n < 1 Then
Console.WriteLine("Factorial = {0}", fact)
Return 1
End If
fact = fact * n
Return Factorial(n - 1, fact)
End Function
End Module

Answer 1

Given the recursive function:
Function Factorial(n As Integer) As Integer
If n <= 1 Then
Return 1
End If
Return Factorial(n - 1) * n
End Function
And a initial call with value of 5:
Dim result As Integer = Factorial(5)
You'd get this sequence:
Call What gets returned
---- -----------------------
F(5) Return Factorial(4) * 5
F(4) Return Factorial(3) * 4
F(3) Return Factorial(2) * 3
F(2) Return Factorial(1) * 2
F(1) Return 1
When we get to F(1), we return a 1, then we "unwind" and move backwards up the call chain, substituting the return value into the previous line where the recursive call was. At each point during the unwind, a new integer value will be calculated (and returned) until we end up with the final answer that gets returned by the original recursive call and assigned to the "result" variable:
Return 1
Return 2 ' 1 * 2
Return 6 ' 2 * 3
Return 24 ' 6 * 4
Return 120 ' 24 * 5

Answer 2

If you're just interested in learning how recursion works then Idle_Mind's answer is good. However, if you just want to computer the factorial of a number, this is much simpler:
Dim Factorial As Integer = 1
For i As Integer = 1 To N
Factorial *= i
Next
where N is the number for which the factorial is desired.