First you would have to sign up a hosting package with afrihost.
Please have a look at our hosting packages:
Linux - http://www.afrihost.com/linux-hosting.php
Once this is complete log into your cpanel click on softtaculous app installer and download wordpress.
If you are still struggling please follow the helpful link below:
You would need to download the zip file which contains the theme
Once this is complete you can log into your backend of your word press >under themes > click on upload themes and upload the zipped file.
Wordpress will then do the rest for you and all you need to do is enable the theme.