Once i have bought the theme what then?
obviously i have to upload the info to the template, are there certain domains i have to use? do i need to have online space to store the site etc?
First, you need yourself a quick injection of knowledge and experience, what is server, server registrars, domain names, DNS, IP, etc.. Wordpress, Joomla, Drupal or whatever you work with.
Next, you need to get to work. Just don’t ask the author on these issues, only when it’s critical. It is your entire responsibility what you do with your site and your new theme license.
Best of luck.
Make it easy on yourself.
What kind of theme did you purchase? WordPress?
Go to hostgator.com and register your domain name (pick anything you want) and buy you “web storage” (aka hosting) there. They have a 1-click install application that will install WordPress for you. Their technical support will help you if get lost somewhere along the way.
Once you have a WordPress site setup, your theme will have documentation that explains how to install it and start customizing it.