Follow this quick guide
1) username xxxx password xxxx
2) passwd xxxxx
3) ssh x.x.x.x x.x.x.x {inside/outside} (Example: SSH 130.226.1.2 255.255.255.255 outside, to enable SSH from 130.226.1.2)
4) crypto key generate rsa modulus 2048
5) aaa authentication ssh console LOCAL