1) In SQL Server Management Studio(SSMS), connect to the database server.
2) Right click on the database you would like to backup, choose tasks, and then backup.
3) In the window that appears choose the full backup option, give it a name, backup to disk, take note of the file location, and click OK.

4) Zip up the .bak file with a program such as 7zip and upload it to sharefile.