To import a large file, click the “+NEW” button in the top right corner of the library page.

Next, select the File Upload option. 

Lastly, there are a few options for getting your file into Gigasheet. The first is to drag the file from your directory to the upload box. You may also select the “Browse” option, which will launch your file directory and you may select your file that way. If you wish to upload your document using Google Drive, DropBox, or OneDrive, please see this article