Let's take the word oil to begin with. Now assume you only want the first letter, o.
Here's how we will do this.
<%
Dim strWord, strLetter

strWord = "oil"

strLetter = Left(strWord,1)

Response.Write strLetter
%>
What we just did was told the server to take the word oil, start from the left and get the letter in the first place.
This will print: o

Now lets say you just want the last letter, l.
<%
Dim strWord, strLetter

strWord = "oil"

strLetter = Right(strWord,1)

Response.Write strLetter
%>
What we just did was told the server to take the word oil, start from the right and get the letter in the first place.
This will print: l

Now we want the letter i. Mid comes into play now.
<%
Dim strWord, strLetter

strWord = "oil"

strLetter = Mid(strWord,2,1)

Response.Write strLetter
%>
We added a number here. What we just did was told the server to take the word oil, start from the second letter in the word, and display one letter.
This will print: i

But, what if the word is not 3 letters long? Let's look at a longer word like server.
<%
Dim strWord, strLetter

strWord = "server"

strLetter = Mid(strWord,4,1)

Response.Write strLetter
%>
What we just did was told the server to take the word server, start from the fourth letter in the word, and display one letter.
This will print: v

If you want more than 1 letter change the number like so:
<%
Dim strWord, strLetter

strWord = "server"

strLetter = Mid(strWord,4,3)

Response.Write strLetter
%>
What we just did was told the server to take the word server, start from the fourth letter in the word, and display one letter.
This will print: ver

There you have it, Left() Mid() and Right() all wrapped up nice and neat.