User transactions are transitory; they are instantiated when the initial form is created and that instantiation is forgotten when the transaction completes. An Instantiation is a collection of variable values which belongs to that transaction which is particular to one user.
Looks for an audit table whose name if same as the groupname of the user transaction, it then compares the variables names in the user transaction to those in the audit table. The values of variables with matching names are are copied from the user transaction to a new row in audit table.