When you are logged in to your iwantmyname account, you can set up 22slides with your domain really easily from our one-click app Marketplace:
https://iwantmyname.com/dashboard/apps/setup/22slides
Just follow the steps and in a matter of seconds your domain will be properly configured.
Then you will also need to add your domain to your 22slides account. Their instructions: How to setup a custom domain name.
You may see things start working within a few minutes, but please remember that it can take up to 48 hours for DNS changes to fully propagate around the internet. So your website may not show up in all browsers immediately.