Adding files in bulk to spreadsheet cells in Google Sheets is a painful task. Clicking manually to more than 3-4 files is going to take a lot of time.
Please view the video below on how to attach files to Google Sheets cells in bulk.
Just install the add-on, upgrade to the Pro version, and drag and drop your files in the upload area. Your files are uploaded and automatically added to the selected cells or column.
As you can see adding files to your Google Sheets is easy with the FileDrop add-on.