Hi -
When you are creating an instance in the first place, it will not get saved.. It just hangs in there at the run time and hence supplying workbook name as test.xlsx will be sufficient. Just use the internal VBO and then create it.
As Vinay suggested first.. first create an excel instance(handle number will be output) and then create the workbook(handle number from the first step will be input and workbookname will be output). Show action is not really mandatory. However just to understand the data is getting copied into the excel or any other operations with excel, show action is recommended. Use Create worksheet action (Workbook name will be input and worksheet name will be output). Then write collection to excel action will be used to write the collection data into the excel. Fields in collection should match with the columns in the excel. After writing data into the excel, please save the Workbook using save workbook as action, in this action you need to provide the complete path of the excel location.