Next, add Player Trade as a dependency under dependencies:
VERSION_HERE would be your exact plugin version, you will not need to update the API version every time a plugin update is out, only when an api update happens.
You can access the Player Trade API by getting the instance. If the plugin hasn't fully loaded the instance will return null, you can use a callback to access the API when its ready.
/*
Accessing the instance, can return null if not loaded.
This instance can also change when a plugin reload has
happened, so its not advisted to use this
*/
PlayerTradeAPI api = PlayerTradeAPI.getInstance();
PlayerTradeAPI.getInstance(api -> { // accessing the instance when its ready.
});