[Help] Can't install any recovery topic

i plan to install Resurrection Remix ® Lollipop v5.2.7 but my phone haven't rooted yet, and doesnt have a recovery yet, when i try to install any recovery,there'll be a signature verification failed, then i go to recovery mode, there'll be "no command" and the broken robot... then its goes to old recovery[galaxy grand recovery]..
Please help...