After downloading the update, you can view the map by doing a pinch motion on the main screen.
If your Snap friends have the feature turned on, you'll be able to see their Bitmoji hovering over their last known location.
Your location only becomes visible to other people when you actually have the Snapchat app open.
If, however, your app has been closed for a while, your Bitmoji will disappear from the map until you open it again.
To ensure people's safety ('cos not everyone is cool with being stalked), there is an opt-in and opt-out feature.
The Snap Map will also show you where Our Story snaps were taken and will highlight areas with high Snapchat activity.
For a full rundown of the update, check out this handy instructional vid: