Brian,
Congratulations on beginning your Mendix journey!
Have you had a look at this How To: https://docs.mendix.com/howto/integration/importing-excel-documents#1-introduction
Mike
***EDIT***
Best practice for using app store modules:
- NEVER change or add anything to an app store module. This ensures that you can upgrade to new future versions of the module with minimal effort
- you can use pages / snippets / microflows etc. anywhere in your app as long as you don’t change them
- if you need to change pages / snippets / microflows, make a copy of these and place the copy in a module of your own (I typically have a single module that I use for these copies, with a folder for each module and the copied objects inside of the folder)
- if you need to extend entities in a module, create a specialization of the module entity in one of your modules
- many modules have Use Me folders which will give you a good starting point (Excel Importer does), and/or and Example folder (Excel Import has this too)
Let me know if you have any questions or anything is not clear.