Install WordPress on your domain. Make sure that you take your time and follow this step by step guide to set up self hosted WordPress.
Install Wp-Ecommerce plugin. This can be installed in two different ways.
Install Plugin from WordPress Dashboard:
Go to your WordPress Dashboard - Plugins - Add New - Search
Search ‘wp-ecommerce’, once search results appear, locate the one who’s developer is ‘mufasa’. Simply click on install, and then active. Plugin is ready to go.
Install Plugin through FTP:
In case if you’ve tighten security on the server and your wp-content folder is write protected, you cannot install the plugin from WordPress Dashboard. You’ll be required to download the plugin from wordpress.org/extend/plugins/wp-e-commerce/.
Once, downloaded and extracted, upload the plugin on your wp-content - Plugins folder via FTP. Now go to WordPress Dashboard - Plugins and activate the plugin.
Once, plugin is set up, you can see ‘Products’ menu in the menu bar in the Admin area from where you can manage products exactly as you write your blog posts. You can add, categorise, edit, remove products, set price, add number of items in inventory etc. It will automatically adjust your inventory depending upon the sales and returns.
Be sure to follow the instructions given above for best results. However, if you face any difficulties then you should go back and try them again. Be sure to take your time so that you do not skip any particular step. If you still have issues then go online and you will find a whole host of websites and forums that deal with E-commerce and WordPress sites. You will find many experts giving their advice, tip and tricks that you can use to help you with anything. You can also post your own questions on a forum to get some more personalised help with whatever issue your are facing.