Hi Hoygen,
Regarding sFlow Agent IP Address, its an optional command. The device periodically checks the existence of the sFlow agent address. If the sFlow agent has no IP address configured, the device automatically selects an interface IP address for the sFlow agent but does not save the selected IP address.
NOTE: • HP recommends configuring an IP address manually for the sFlow agent.
And yes, you need to configure your Manage Engine network analyzers IP address as your collector on the switch.
Eg: sflow collector 2 ip 3.3.3.2 description netserver