Here's what I did to write first script on NANO 33 BLE.
Hope this will be a help for someone.
1.Pluged in the device to PC with USB cable.
2.Launched Ardino IDE and saw a popup that says "It needs to install a package, Arduino Mbed os boards to use NANO 33 BLE". If you don't see it at this point, maybe the USB cable is not the right one.
3.Installed the package, unplugged the arduino device, closed the IDE then plugged the device again, reopend the IDE.
- From Tools, selected Arduino NANO 33 BLE as doard, com3 (Arduino Nano 33 BLE) as serial port.
5.Press the right-arrow button to write the script. Done.