Check that the IOS supports Netflow by adding “ip route-cache flow” to an interface.  If the command is successful  the IOS supports Netflow.

If the command errors on “flow” then upgrade IOS to a version that supports Netflow. Use Cisco feature navigator to find the correct IOS. Search by Feature, Add Netflow to the selected features.

www.cisco.com/go/fn

Set Netflow for each interface

Interface Serial0/0
Ip route-cache flow
Bandwidth 1536
Exit

In global config

ip flow-export source FastEthernet0
ip flow-export version 5
ip flow-export destination 192.168.10.50 9996
ip flow-cache timeout active
ip flow-cache timeout inactive 15
snmp-server ifindex persist
Show  IP flow export
Show IP cache flow

To collect NBAR stats

Ip cef
Interface S0/0
Ip nbar protocol-discovery
Show ip nbar protocol-discovery