I'm new to the drone world. I just picked up an Eochine E013. The manual is not very clear/complete. The manual shows a "Left Rotation fine tuning" button and a "Right spin fine tuning" button on the left side of the controller. On the right side of the controller, the manual shows keys labeled "Pre-fine", "Fine tuning key", "Right trim key", and "Left fine key". The instructions don't clearly describe the functions of these buttons, or how to use them. Can anyone help, or point me to help for a better description for, and usage example for these keys? Thanks in advance.