How to use driver object in webdriverio with appium

While testing with appium and webdriverio, there should be a driver global object like the browser object, but when I try using it the test doesn't compile because it doesn't exist! it's mentioned here:

https://webdriver.io/docs/browserobject.html

and it's needed for all appium's native commands in here:

https://webdriver.io/docs/api/appium.html

But I don't know how to get it working. (for the browser object I just use it, although the IDE doesn't recognize it, but it works, on contrast to the driver object)