I am going to give a step by step details on installing DS 4.2 on SQL Server 2012. Before installing one has to meet all the prerequisites like .NET, Adobe flash player, CMC (either IPS or BOE) and MS Office. This is a stand alone installation with BOE Edge as CMC and SQL Server 2012 as the database on Windows 2008 R2 server.
Once you start the installation you will be prompted to read the documents and video that help in the installation process.
The next screen will show the pre-requisites check and without meeting the necessary pre-requsities, installation will not continue further.
The next screen will show the deployment platform message on best practices for installing IS along with DS
Accept the license agreement and move forward -
Enter the product key and click next -
Select the installation path, i have decided to be in the default C drive.
Select the languages you want to install, i have selected only the default as English.
Like in 4.x versions we have to configure DS with repo by entering CMS credentials. The servers (SIA) will stop and start automatically.
During the installation process, once can choose to install with default configuration as well as skip the configuration to set up all later.
Since this is a stand alone installation on one server, i chose to have both the server and client in one place. All components as shown in the picture were selected for installation.
Select the database server name -
Create a repo database connection. The default port for the connection would be 1433, but some times when a dynamic port value is specified you need to key in that value for connection. The dynamic port value can found under sql server configuration manager of installation directory.
I have used the recommended account which is the Administrator login account in my case -
After this next step is installation and after installation the DS will display the list of components installed.
Hope you have enjoyed reading it 
Arun