your don’t need to create a database one.com already created one for, check your email 2 of 2 from one.com they sent you the information about your ftp user name, database user name etc.
what you can do:
1. download wordpress from wordpress.org on your computer
2. unzip it
3. open filezilla and enter the info which one.com sent you and press quickconnect( if you don’t have filezilla download it from filezilla-project.org/download.php or google it, its free)
4. upload wordpress files to the root dir, its ‘public_html’.
5. Run the WordPress installation ‘http://example.com/wp-admin/install.php’ in a web browser. ( change example.com to your domain name)
6. wp installer ask you some informaion which you have from one.com eamil 2 of 2.
That is all… good luck