To create and use a new variable, you will have to do the following:

• Find the names of variables you want to recode or include in a compute expression.
  You can use the "Search" function, or look in the tree list of variables, or look in the online codebook.

• Select the appropriate action on the option screen (either to recode or to compute).
  Put your cursor over 'Create Variable', then select either 'Recode variables' or 'Compute a new variable'.

• Specify the recode rules or the compute expression.
  (See some suggestions.)

• Use the new variable in an analysis.

Try this out with the GSS Dataset