The manual is incorrect. This device requires additional power supply, which is only available via USB 3.0 or higher. When connecting with USB 2.0 or older, the device doesn't even turn on, so your computer doesn't even recognize it. On Windows it is possible that the driver will increase the USB 2.0 performance to allow it to work. On Ubuntu 18.04, just connect to USB 3 and wait 10 seconds. Then select your wireless network (no additional steps required). The same applies to all Linux operating systems created in 2018 or later. This is legacy Wi-Fi technology so don't expect it to be very fast or connect to a 5GHz network. For general use, it gets the job done.
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