The kernel has been built with the appropriate support, the initrd image has been constructed, and the boot-loader has been configured. You are now ready to reboot your system using your EVMS volume as the root file system.
In general, you should still run evms_activate during your regular boot scripts. Even though the volumes will already be activated, running evms_activate makes sure the device files in /dev/evms correctly reflect the device numbers assigned by Device Mapper.