Here is a config that can be copied and pasted; note the 1024 is in response to the "crypto key generate rsa" statement. Keys can be 512 or 1024 bits.
conf t
!
ip domain-name mydomain
!
crypto key generate rsa
1024
!
aaa new-model
aaa authentication login default local
aaa authorization exec default local
!
line vty 0 15
transport input ssh
!
