Specify the substitution variable number for the variable that has been defined for the First Level Text. Variables are number &1, &2, etc.
A substitution variable is used to pass a value to a message. For example, a message might have the following text: "File &1 in library &2 cannot be compiled." The value of substitution variable &1 can be passed to the message so that the text becomes: "File PSLMST in library DEMOLIB cannot be compiled".