SQL Server Management Studio is the Microsoft utility that allows modification of settings and objects in an SQL Server (usually used by administrators or developers)
A Free version (Express) can be downloaded from Microsoft
(Search "Microsoft SQL Server Express" if the link above changes to find it in google or bing)
All related SQL files are found at that link
Download the "SQLManagementStudio_x86_ENU.exe" (for 32 bit platforms) or "SQLManagementStudio_x64_ENU.exe" (for 64 bit platforms)
Run the file and perform a FULL standard install.