Early setup is about as simple as possible. Find a three-prong outlet that's in a convenient spot for the gadget you want to operate and plug in the Smart Plug. Then, download the app and follow the steps -- this is where things got more complicated.
I had a really hard time actually finding the Mydlink Smart Plug app in both the iOS and Android app stores. In the Google Play store it's called Mydlink WiFi Smart Plug and in iTunes it's called Smart Plug.
Once I found and downloaded both apps, setup got easier, but there were still a couple of confusing parts. For example, the setup menu gives you the option of a WPS setup or a manual setup. If you have a router with WPS, then this is fairly straightforward. If you don't, you have to go the manual setup route. That's the option I chose and you have to use a six-digit pin code located on a small card that's included in the box (it's also on the back of your plug, but that's plugged in at this point, so that's no help). After I entered the code, I selected the office Wi-Fi network and it connected.
After setup, I plugged a nearby lamp into the Wi-Fi Smart Plug and was able to control it via the app. I created schedules, checked the lamp's wattage, and monitored its temperature readings from both Wi-Fi and cellular connections on my iPhone 5 and a Motorola Droid Maxx.
Things were going well, but then I ran into a curious problem while using the iOS app. You're supposed to be able to receive reminders based on the schedules you set. However, the enable button for this function was grayed out and I couldn't slide it over to "on." I didn't have the same problem in the Android app.
The biggest issue I encountered, though, happened when I unplugged the Smart Plug. Even if it had only been disconnected for a few minutes, it didn't always remember the product I had just successfully set up. This happened often enough that I kept the small card with my six-digit code handy, knowing that I would have to start the setup process all over again.
Now, a lot of you will probably pick the product you want to control and leave it plugged in. Just be aware that if you did decide to remove it temporarily (no matter how briefly), the app might not reflect all those steps you completed earlier. I have three different Belkin WeMo products set up in my WeMo app and at various times certain ones are plugged in and connected and others aren't. Still, every time I reconnect them, they always dutifully reappear in the list of products as if they had been there all along.
While I was initially intrigued by a device that costs the same as Belkin's standard WeMo Switch, but offers energy usage information similar to Belkin's more expensive $60 WeMo Insight Switch, D-Link's Wi-Fi Smart Plug disappointed at almost every turn. Simply put, it has too many inconsistencies to recommend. Consider one of the Belkin smart switches if you want something that actually remembers the products you set up and has the added bonus of IFTTT compatibility.