TThe Excel file & FileMaker Pro have the same fields.
You can script the "import records" script step to target a specific worksheet, and save a field order for mapping the import.
Import Records - FileMaker Pro 17 Advanced Help
I'd recommend scripting a button where the user can select the file for import and the rest is taken care of them. Can be a fairly simple one line script with some of the settings in the Import Records script step preconfigured.
I'm a novice when it comes to these kind of things. Is there somewhere I can find a created script that I can use for this?
If you don't know how to create a script using a single script step, then you really do need to learn the basics about FileMaker before trying to develop your own app. The document I linked to above IS the example of what script step to use. You only need the one script step to import records. The options of that script step specify what worksheet to use and what field order to set.
Most people these days are using Lynda.com as a starter training course:
you can skip ahead to the "scripting" chapter if you want, but I'd recommend seriously investing the ~6-10 hours to get through the basics course. Lynda.com has a free trial month and most library systems have a subscription you can use in the library as well.
YouTube is also a good resource, here's a video for how to create scripts:
FileMaker Scripting - YouTube
Then Richard Carlton has the book for you: FileMaker 16 Manual for Novices
Info about their version for FileMaker 17 is there, too.
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