@ning johnny zhao I think the error as per your log:
"ModuleExceptionMessage:InvalidDataset: Dataset is not valid. Input data type EXCEL_WORKBOOK is unrecognized."
indicates that the data module connected to split data isn't a compatible format which split data module can use. Generally, data passed to split data needs to have selected columns with normalization to ensure the right split is used for training and the remaining for testing or validation. Based on the above screen shot it looks like you have not used some of these modules. If you have just started using Azure ML studio, I would recommend going through MS learn courses that have guided steps on using designer to build jobs and endpoints. In this case, a simple regression experiment can be built using this course. The course contains a hands-on lab that further explains the significance of using each step.
Also, check out other learn courses to use Azure ML from the library.
I hope this helps!!
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