my                               # declare the variables in the local scope (guarantees you won't overwrite a variable already in use or capture a value already assigned)
($_configParam,$_paramValue)     # A list of variable names that you are declaring, note that coma separated variables between parenthesis are treated similarly to an array for assignment purposes
=                                # and as you declare them you assign them a value
  split(                         # a Perl function that splits strings on the basis of a regular expression
/\s*=\s*/                        # the regular expression to use in the split. any number of space characters, followed by an equals sign followed by any number of space characters
, $_                             #  The second part of the split statement, the string to be split $_ is the default variable, you will see it a lot.
, 2);                            #  Limit the split to 2 values, close the call to split and terminste the line with a semi-colon
$configParamHash{$_configParam}  # in an indexed list keyed on the parameter name
= $_paramValue;                  # assign the value above to a hash entry keyed on the parameter name