coachMarker.dataSource = self
coachMarker.delegate = self
coachMarker.show()

extension ViewController: GLWalkThroughDataSource {
    
    func numberOfItems() -> Int {
        return 1
    }
    
    func configForItemAtIndex(index: Int) -> GLWalkThroughConfig {
        switch index {
        case 0:
            var config = GLWalkThroughConfig()
            config.title = "Home Screen"
            config.subtitle = "Here you can explore Services, Articles, plans"
            config.frameOverWindow = CGRect(x: 50, y: 50, width: 100, height: 100)
            config.position = .topLeft
            return config
        default:
            return GLWalkThroughConfig()
        }
    }
}