If you want to transfer files from your PC to the One Plus Nord, it is generally recommended to do this via a USB cable connection. This means that you connect the One Plus Nord to the USB port of your computer using the cable provided.
However, it is often the case that the smartphone's internal memory is not displayed as removable disk, but the smartphone is simply being charged.
If this also applies to your device, simply use the following steps to solve the problem.
One Plus Nord USB connection - step by step
1. connect the smartphone to the PC using the USB cable provided
2. unlock the One Plus Nord if it is secured by pin, password, pattern, fingerprint etc.
Drag the status bar from the top of the display and select "Android system".
4. go to "More USB Options".
Select "Transfer files".
Your One Plus Nord internal memory should now be visible within the Windows file explorer and you should be able to access the data on your smartphone. You can now copy them to create a backup or transfer data to the smartphone.