Newbie needs Excel suggestions with a simple script

Question

I want to search on a specific column in an excel file. I'm curious how frequently a particular "letter/character" has been utilised. It's the letter "x" in my instance. I eventually came across this formula after some research:

=COUNTIF(D2:D48,"FIDELIO")

the problem here is, I always get an error message: 

If I write the Code with an " ` " in front like this:

`=COUNTIF(D2:D48,"FIDELIO")

Excel simply writes the code to me as text rather than as code.

Tried to write the Code with an "`" in front like this:

`=COUNTIF(D2:D48,"FIDELIO")

Excel then simply writes me the code as text rather than as a code. Here is a more image:

Answer 1

Formula to Count the Number of Occurrences of a Single Character in a Range

=SUM(LEN(range)-LEN(SUBSTITUTE(range,"a","")))