To map the Opportunity field Account Soft Credit <api field name:LOGINACCESS_Account_Soft_Credit_c> to the Account Soft Credit object using "Influencer" as the role, first you have to make sure that the field has been created and is visible under the Opportunity object.
Once field has been successfully created, follow the steps below to map:
1. Go to Campaign Importer. Click on Opportunity-Account Soft Credit Field Mappings.
2. Under Opportunity Field(Related Account), select Soft Credit Account and choose Influencer for the Contact Role.
3. Click on Add Mapping. You should then see the mapping below the fields.
Now that the setup is done, on your Opportunity, if you select an Account in your Account Soft Credit field, an Account Soft Credit is auto created in the Opportunity related list.
The Account selected will also have the Account Soft Credits associated with the account under Opportunities (Account Soft Credit) related list.
Once this is completed, you can follow these instructions to display the sum of Account Soft Credits per Account.