So, 1) above, you would be overwriting the first file with the second one, because the Save As filename isn't dynamic. 2) ".xlsx" is already declared in the 'Document format' parameter of the "Close Excel", so we do not want to also put it in the 'Document path' parameter, this will cause it to double up.
Here is what we want Close Excel to look like:

All variables have properties. In this example, %CurrentItem% is a 'File' variable type. I keep this link saved on my desktop for reference:
https://docs.microsoft.com/en-us/power-automate/desktop-flows/datatype-properties
It lists all properties for all variable types, here is a snippet from files:

So, '%CurrentItem.Directory% is the same folder that you got the file from, and %CurrentItem.NameWithoutExtension% is just that. Don't forget the "\" between the two.
If you have any trouble, let me know.