The Install version works fine but I wanted to have access to all the DNN code while developing modules to understand how DNN works (due to lack of documentation to some APIs) and for deep debugging purposes. For some reason the DNN source version never worked for me. I always get a divide by zero error during the new DNN Installation. It happens every time in different 7.x version and on different machines. Because the easy workaround below works for me, I didn't bother investigating the source of the error.

Installation Steps:

1- Unzip the source zip into a folder.

2- Unzip the install zip (another download) on top of the 'website' folder from step 1. OK to overwrite all the files

3- Create an empty database in sql server

4- Modify web.config to use the proper connectionstring properties, username, password and database name from step 3.

5- Open DNN_PlatformNoTests.sln in Visual Studio. (That's the solution file I decided to use. I don't need the test projects. The other solution files might work but I didn't try)

6- Make the website project the startup project

7- Run. This should start the new installation process and then your DNN website is ready. 

8- Some code are in separate Codeplex projects. I think the DDR Menu is one of them.