How can I solve digispark [not connected] problem in Arduino IDE?

Hello guys I'm working on a project using digispark (Attiny85).

I downloaded arduino IDE then I added this URL (http://digistump.com/package_digistump_index.json) to Additional Boards Manager URLs. I installed for Digistump AVR Boards. I selected Digispark (Default - 16.5mhz) board but on the bottom right of the Arduino IDE inteface I got this :

and this how my device manager looks:

Disclaimer: I'm on Linux, and you are most probably on Windows. All my insight bases on my local PC and the clone of a Digispark I have.

When using the ATtiny85 and the Digispark Uploader, it is correct that you don't see a connection. Since the ATtiny85 has no USB module and no other hardware component for USB is added, the Digispark only communicates as USB device during the 5 seconds after power-up/reset. (Exception: You flash a sketch that does USB.)

If you want to flash your sketch, disconnect the Digispark from the PC, click the "upload" button and wait until the message window presents the message:

Plug in device now... (will timeout in 60 seconds)

You might need to enlarge the message panel below the source code to see this.

Now you have about 60 seconds to reconnect the Digispark. Be patient, it takes a second or more until the flashing begins. All is well if after some seconds the Digispark Uploader tells you so. In case of an error it will tell you this, too.

The documentation describes this in detail, and has some links for troubleshooting.