Field mappings can be done from the S4S Experience Form Mapping Wizard module which can be accessed from the Sitecore launch page pad as follows.
Next Step
Select Options in S4S Experience Form Mapping Wizard
...
Field mappings can be done from the S4S Experience Form Mapping Wizard module which can be accessed from the Sitecore launch page pad as follows.
Select Options in S4S Experience Form Mapping Wizard
...