Hello,
The device will not remove its current config when you connect it to the configurator,
If you want to save the device configuration file, follow the steps that I have provided above then you can modify the device configuration without worrying that the previous config is being overwritten.
Load from the device will only be visible if the device is connected to the configurator, if the device is not connected it will not be available.
Please check this youtube video: GPS Tracker General Quick Start Guide | Teltonika
Best Regards
Maynard C