Uploading only puts the file on the server for it to then be used for other operations... For example, if it is known that the file is going to have a large number of rows and from past experience importing that many rows will be a problem, it is possible to split the file after it is uploaded and before it is imported...

Upload puts on server, import puts in database. Much like export pulls from database (puts on server), download pulls from server (brings to local computer)...

Not quite there yet.. Find the file in the list down on the screen, select import to the right of the filename... (after you have made your backup in case there are any issues. :) )