Grid home consists of the Oracle Clusterware and ASM. But Grid Infra and RAC DB must be install different home.
First install clusterware then install RAC
If you want to use ASM and Oracle Restart GI can be installed in single server mode .
Grid infra run alone. You can use application like other clusterware
Voting file backed automaticly(configuration change).You can restore crsctl.
SCAN VIP three ip. one vip for each node register DNS or Grid Naming Service
Connect node then Start and Stop CRS crsctl start crs crsctl stop crs
crsctl start cluster start all nodes