Currently there is no way to import data from a CSV or XLS or Sheets file which is held in a shared drive. However, it is possible to make a copy of a file from a Shared drive and paste it into a normal folder. You can then get Sheetsie to fetch the data from the file in a new folder. It is just a matter of running the imports in the correct sequence.
To do this you will need to
1 - create (or use) a folder in your own drive - get the URL of the folder - add a new row to the import settings sheet - In the new row
2 - paste the URL from above into Col B as the Destination Folder URL
3 - set the source file type to Shared Drive
4 - set the source folder (Col K) to be the URL of the shared drive
5 - set the source file name (Col L) to the name of the file you want to import
6 - Run the import process that will import the file from your shared drive to your folder
7 - In a lower row (so that it runs after the import from the shared drive), create a new row of import settings for the file to import it from the new folder into your chosen destination (with the file type as xls or csv or sheets etc)
The second import settings have to be in a lower row because the sequence is important. So, when you run the import process it will copy the file from the shared drive first and then run the import from xls file to your destination.