There are two main ways you can upload a file to your Workbook.

When you open an empty sheet, you will likely have an option to upload a file to that sheet. When you click on the "Upload File" button, you'll see a modal pop up where you can browse your computer and find the file that you wish to map to this sheet.

When you upload your file directly to a sheet, the sheet you are uploading to will be selected automatically if there are multiple sheets in your space, and the mapping process should start as soon as the file has been uploaded and is ready to be mapped.

If you are in a space where the sidebar is enabled, you'll have an option to access a Files menu. Here, you should see a dropzone where you can upload a file. If there are already files uploaded to this space, you'll see them listed and can click the "upload file" button at the top to bring up a modal where you can upload your file.

Once your file is uploaded and ready to map, you'll see a button labeled "Import" that you can click on to start the mapping process and get the data from your file into the Review Table. Unlike uploading directly to a sheet, the mapping process will not start automatically here, but instead you'll select the appropriate sheet to map this file to, as well as the appropriate sheet in the incoming file if applicable.

You can do a few things with your files when in the Files menu. Once uploaded, you can re-download a file from this area. You can also delete a file, both from the menu above the list of files as well as the actions menu to the right of your file.

You'll also see an "Available Downloads" tab at the top of this screen. If you are downloading a large set of records from your sheet or your space has an action to initiate a download, you may find the file here for you to access when it's ready.