How to download/install Domain Mapping plugin

I have started wpmudev free trial and installed this plugin by doing following steps:
1. Configured the Wordpress installation to multi site allowed.
2. I have then Network activated wpmudev plugin

Now i have to install Domain Mapping plugin, so that i can create more domains in it. But when i click on "Download" link in plugins page in WP Dashboard wpmudev, it takes me to this page :

And when i click on "Install" link on this page, it asks me about the website in want to install it to and then it takes me to WP Dashboard of wpmudev.

It seems to be endless loop. Can you guide me how can i install Domain Mapping plugin.