First, we are installing SQL Management after doing that we will install SQL DB engine
Step 1. Click on New SQL Server Stand Alone installation
Step 2. Click on next button ( Here is Product Updates Window )
Step 3. Here is time to select Installation Type.
Please select the radio button of “Add features to an existing instance of SQL SERVER 2012” Click on Next Button
Step 4. Feature Selection
Select Features according to the above screenshot & click on next button
Step – 6. Error Reporting Window ( Please click on next button )
Step – 7. Complete the installation
Click on ok button & restart. Your installation is done successfully.