It's a sad fact that many vendors which claim to support Linux don't really support it.
It is a Wrong Answer for the vendor to expect clients to download an unsigned driver file from the Web to make their device work for Linux. Presumably, the provided file is source code which will then have to be compiled in order to be used. If your experience is anything like mine with ASUS, the provided code will be stale and will fail to compile.
The good news is that you might not have to deal with all that. The first step is to determine the device ID of the adapter. It appears to be a USB wireless adapter, so you will use the
lsusb command to get this information. For non-USB devices you will generally use
If you post the output of the command here, I will assist you in interpreting it. The information you want to extract from the output of the command is a hexadecimal number of the format "nnnn:nnnn" immediately following the string "ID" on the line that contains the vendor's name. Here's what my lsusb looks like:
Bus 002 Device 002: ID 045e:00dd Microsoft Corp.
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 003: ID 046d:0807 Logitech, Inc.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Once you have determined the device ID for the adapter, you can search for the appropriate kernel module for it. Googling the ID number along with "linux" or "kernel" sometimes works. There are also compatibility lists like this:
You'll notice that there is no vendor listing for Rosewill on this list. Most likely that means the vendor uses another company's chipset- the other company's name will then be the one that shows up in lsusb's output.
Once you have determined the correct driver for the device, simply do
sudo modprobe [module-name] to load the module and see if it works. If you get a Module Not Found error, that probably means the module isn't installed. If this is the case, you will likely need to install the linux-backports-modules-compat-wireless package.