It depends on the use you will give, and there are different ways to do it. As Yashwani told you, you can just use VIPs and Nat pools.
For example, if you are going to publish web services, you can use VIPs:
- VIP1 : 172.16.0.2 to 192.168.12.2; VIP2: 172.16.0.3 to 192.168.12.3 and so on.... In that case, when traffic arrives to your public IP, will be nat'd to your private one (the subnet 192.168.12.0/24 is you LAN/DMZ network in my example).
Another option (or you can use both according your needs) is to create a nat pool for outbound traffic.
- NAT POOL: 172.16.0.4 to 172.16.0.5. Then you can use this pool into a firewall policy to perform source nat for outbound traffic to internet.