I'm using it in iOS 8.4, I set it up in each event just like when I'm needing to drive somewhere. The only sticking point in Maps is that that app needs to be able to recognize that one can walk to that place - I'm on a large island and Maps doesn't recognize that I can walk on either bridge off the island to get somewhere 😡. So, if Maps recognizes that you can walk to your chosen location...
Start the event/meeting (I use meetings for this...). Tap on the Location field, and set up a location - if it's a place that's not in your Contacts or Recents, enter an address or a location in the Location Field and select the address. The next step is to move to the Travel Time field and turn it on for that event - a few seconds later you'll see options for driving and walking travel times.
After opting for walking in the previous option, move to the Alert field and tap on that, and you'll be presented with Alert options that address a notification prior to the travel time (0/5/10/30/60/120 minutes before needing to leave).
If the Maps app can't get you from here to there by walking, there's this cool app named Google Maps... 😳
