You are not supposed to enter the $.
The $ represents the shell/terminal prompt. This is the string of characters that appear in your terminal when it is waiting for input, although $ typically indicates some flavour of unix, e.g. linux.
Your terminal will probably use a different prompt, e.g.
[user@localhost ~]$
Or, if you are using a Windows terminal you might see :
C:\>
or
C:\WINDOWS>