I'm stumbled into the same question, and somehow using the appium-boilerplate confused me. So I create my own GitHub repository for this specific matter. You can check my Medium's article here for references if you still haven't find the answer for this question.

https://medium.com/@zorozeri/test-automation-on-android-apps-using-webdriverio-2f39da6a338c

This is only a very simple sample for the Android Test Automation using WebdriverIO. You can change the apps and the code by yourself after you grasp the concept.

And this is for the iOS one : https://medium.com/@zorozeri/test-automation-on-ios-apps-using-webdriverio-with-allure-report-b3ed46d3c0a8