Update locative documentation

source/_components/device_tracker.locative.markdown

@@ -11,8 +11,7 @@ logo: locative.png
 ha_category: Presence Detection
 ---
 
-
-This platform allows you to detect presence using [Locative](https://my.locative.io/). Locative allows users to track their location on iOS devices.
+This platform allows you to detect presence using [Locative](https://my.locative.io/). Locative is an [open source](https://github.com/LocativeHQ/ios-app) app for iOS that allows users to set up a `GET` or `POST` request when a geofence is entered or exited. This can be configured with Home Assistant to update your location.
 
 To integrate Locative in Home Assistant, add the following section to your `configuration.yaml` file:
 
@@ -21,3 +20,13 @@ To integrate Locative in Home Assistant, add the following section to your `conf
 device_tracker:
   platform: locative
 ```
+
+To configure Locative, you must set up the app to send a `GET` request to your Home Assistant server at `http://<ha_server>/api/locative`. Make sure to include the API password if you have configured a password in Home Assistant (add `?api_password=<password>` to the end of the URL). When you enter or exit a geofence, Locative will send a `GET` request to that URL, updating Home Assistant.
+
+<p class='img'>
+  <img src='{{site_root}}/images/screenshots/locative.png'/>
+</p>
+
+When you enter a geofence, your location name in Home Assistant will be set to the name of the geofence in Locative. When you exit a geofence, your location name in Home Assistant will be set to "not home".
+
+To use Locative in combination with another device tracker, such as [nmap](/components/device_tracker.nmap_scanner/) or [Netgear](/components/device_tracker.netgear/), fill in the `mac` field to the Locative entry in `known_devices.yaml` with the MAC address of the device you want to track. The state of the device will be determined by the source that reported last.