SEEED nRF52840 usb port numeration

Hello, I’m a new seeed user.
I purchased 2 x Seeed nRF52840 (sense) boards. I’m using PC support windows 7.
After connecting the board to the PC the boards recognize at the device manager but doesn’t get port
number !!
So, I can’t start to work with them/
Appreciate for the support on this issue.

Hello, I think your PC may not have a serial port related driver

Dear nengyu
Thanks for yours reply.
The other seeed board (XIAO SAMD21) works o.k, while connecting to the USB port.
Appreciate if you can guide me to drivers for this board.
Thanks from advanced