Setting up Wordpress Multi-Domains

Hi, I'm a little confused and hope you can help out.

Our company has registered different domains for countries we do business in. Such as,, and so forth.

Each site will use the same theme and plugins. Only the content will vary.

Hence we thought your multi domains plugin would be ideal for us. We have set up a master site and installed Wordpress multisites following these instructions found here

We have also installed Domain Mapping and Multidomain plugins. But the next steps are unclear and we have not been able to edit any sites we have added.

Cheers. Steve