If it is excel, you can use the excel importer https://appstore.home.mendix.com/link/app/72/
Import the sheet to a single temporary entity and in a post import step you can create the objects for your different entities.
Pitty that you are on version 7.23. For version 8.6 you can create a new app using this excel sheet. Then publish the entities as webservice and consume that webservice in your 7.23 version to get the data transfered to 7.23.
It might seems more work, but it is actually just three steps that are well to do and nice to try.
Unfortunately I am confused about your question related to the topic. But for your question, do you want to create a Mendix App with an Excel sheet by this new Mendix 8 feature or do you want to import an excel sheet by the Excel importer?