Read the docs to see how to install it on the mbr.
Make install just installs the user land tools on your disk, but it will not put the loader on the master boot record of your disk. You will probably need to configure it properly as well. I don't know if grub2 can use unmodified grub.conf/menu.lst files. Changing the bootloader is something that I would not do blindly, since you can render your system unbootable.