public class MyScreen_PageObject{

@FindBy annotation with locator value
WebElement field;

//staff
AppiumFieldDecorator afd = new AppiumFieldDecorator(driver);
PageFactory.initElements(afd, this);
//staff

public void clickOnField(){
  afd.resetImplicitlyWaitTimeOut(2, TimeUnit.SECONDS);
  //It will wait for element is present for 2 seconds.
  field.click();
}