Hey Md,
Campaigns - Access (query) them by either using the 'Compare Custom Object Fields' decision step or by using the 'Shared Filter Member?' decision step, and setting the shared filter to look into the desired CDO. The shared filter is normally used for more complex criteria.
Forms - On the processing step there is a step called 'Update Custom Object from Form Data' .. you can map form data to populate on custom objects here.
In case of the forms you have to know what data types (text,date,number) are being populated to assure this works properly. In case of date the american standard mm/dd/yyyy works fine.
