Does the license show up like this? Then you are ready to go.
show license
Index Package Name Lid Slot License Type Status License Period
1 IP_ROUTE_SCALE $x M normal active unlimited
Else you need to copy it via TFTP
copy tftp license $TFTPSERVER $FILE
System-max:
system-max ip-cache 1200000
system-max ip-route 1200000
system-max ipv6-cache 120000
system-max ipv6-route 120000