From the Home Screen, click on Locations, then 'Add a Location'. Don't know the address? Don't worry. With the Location Selector, you can drag and drop a pin on that basketball court down the street and it will populate the address or will use the geo-coordinates. Just give it a name and type of location and you're good to go! Now when you go back to Locations you'll see it in your 'Nearby' list. If you play there a lot, add it as a Favorite so you can always find it quickly.
Go to Add a Location
and fill out the information and save it! Very simple.