Hello! Providing your 'FULL BACKUP' has backed up your wordpress files in your root/httpdocs and also the accompanying database, and of course none of your hosting settings have changed, you should be able to re-upload your wordpress files via an FTP client and import your database content via phpMyAdmin within your cPanel.
Any content previously backed up, i.e posts, categories, users etc. will be stored in your database or MySQL dump.
Depending on how the 'FULL BACKUP' has exported your database the SQL query may needs some minor tweaks. For example, the queries may dictate to update any existing tables with the said structure/content and therefore may fail if you have not already uploaded the default wordpress tables into your database.
In other cases, which is what I tend to use when transferring databases to another domain, your SQL query can be slightly modified to automatically create required tables and then insert your content, if the tables do not already exist.
So basically, in short, unless you have a backup of your database and not just your websites files you will not be able to restore any previous content.
If you don't understand anything I have mentioned or would like me to help further just ask :)
Hope this helps, Danny.