For this tutorial, we will be using TIMERS. This isn't the only way to do this, documentcompleted is another way, but I have yet to learn that throughly, so here we go:

Code:
Dim s As Integer = 1
This will declare s as the number 1. This will be very important later on, so make sure you have this carved into stone in your head.

Code:
WebBrowser1.Navigate("url")
This will navigate to the URL of the site, you want to put this INSIDE a timer so it will repeat it after it enters the text into the textboxes on the site.

Code:
WebBrowser1.Document.GetElementById("ID").SetAttribute("value", TextBox1.Text)
or
WebBrowser1.Document.GetElementById("ID").SetAttribute("value", "text")
The top piece of code will search the web browser till it finds the ID of the textbox you want text entered into. You can find IDs of a site by using firebug or using google chrome. When the ID is found that you want text entered into, it will take whatever is in TextBox1 and change the value of the ID you have chosen.

The lower piece of coding will basically do the same thing as the top part except it will change the value of the ID you chose to the text you put. You can change the text by changing what is in the parentheses like so...

Code:
WebBrowser1.Document.GetElementById("ID").SetAttribute("value", "test")
to
WebBrowser1.Document.GetElementById("ID").SetAttribute("value", "Restless is King")
Make sure if you want text from a textbox on your form, you remove the parentheses and add TextBox1.text, but to add them if you want preset text.

Code:
WebBrowser1.Document.GetElementById("ID").InvokeMember("click")
This will find the ID of the button that you have put, and it will simply invoke a click. This will submit anything you have put into the textboxes.

Code:
s += 1
You will want to add this towards the end of your code, this will increase the integer we declared earlier, s, by 1.

Code:
Label1.text = s
This will change Label1 to whatever s equals. This will help people see how many samples they have ordered, and you can add a feature that stops the bot after entering a chosen amount by the user.

Code:
If s = TextBox2.text Then
Timer1.stop
Timer2.stop
Messagebox.show("Your samples have been reaches")
End If
This will add the feature I was talking about earlier, and will stop when s reaches the number entered in the textbox.

Important codes:
Code:
Timer1.Start/Stop
Timer2.Start/Stop
Button1.Enabled = True/False
TextBox1.text = True/False
After notes:
How to do gmail + trick:

Code:
        WebBrowser1.Document.GetElementById("Email ID").SetAttribute("value", TextBox1.Text & "+" & s & "@gmail.com")
This will take the email entered in TextBox1 (without @gmail.com) and add (&) the "+" and then once it adds that, it will take whatever s is at and use it for the number in the gmail trick, it will then add "@gmail.com".

Have any suggestions? Let me know!