To work with SVN I would recommend you to install some SVN client. I use TortoiseSVN. It is free and nice.

After installing you will need to right click some folder, then choose "Checkout" and put this URL into a respective field.
http://svn.ext.net/premium/trunk/

It will download all the required sources. Then run a Visual Studio solution file you need (.sln files in the root). Then build. So, you will get required dlls in the bin folder.