NOTE: a midspan adds PoE to one data port at a time. So if you connect LAN 1 to a data port on your switch you'll have POE on port 1 of the midspan.. To get POE on port 2, you need to add a patch cable on LAN 2 back to the switch, And so on.
Then connect the POE port to your PoE enabled device.
WARNING: this is a passive PoE midspan, meaning it does not negotiate the IEEE 802.3af standard before delivering power. What does that mean for you? You should only connect the POE ports to a PoE enabled device. Connecting it to a laptop or other non-PoE device will damage the network card on your device.
So why even use a passive PoE midspan? Besides being very cost effective, they're simple, robust devices that work well even when you forget about them. So as long as the connected device is PoE and no one can unplug it - say a security camera or wifi access point - it makes sense.