If you really don't want to figure out all the individual roles and features, run :
import-module servermanagerThis will install all the necessary roles for SCOM 2012 R2. If you get CGI/ASP handlers not being registered, restart the server.
add-windowsfeature Web-Server,NET-Framework-45-ASPNET
add-windowsfeature Web-Asp-Net,Web-Asp-Net45,Web-Metabase,Web-Windows-Auth,Web-Request-Monitor,Web-Mgmt-Console,NET-WCF-HTTP-Activation45