Khoros Salesforce Integration in Mod Tools Usage and Workarounds

Hi All,

How can I Post and Get Data from Salesforce Custom Fields?
Like I need to make users submit a custom form which will be stored into the Salesforce  Custom Field Objects (eg. userName__c, userId__c ). When the user visits that page next time it will fetch that submitted data from Salesforce and show it to the user. Is there any way to achieve this in using this integration? If Yes then does it requires separate API calls and Endpoints? I am very new to this Integration. So every suggestion and guidance will be welcomed. 

NOTE: I have gone through this documentation but it didn't help much.