There is not much to do at this point but wait until the process finishes. The length of the process depends on the size and number of files to copy.
Upon launching the Rufus app, it should be able to detect the flash drive immediately.Make sure that you get the latest release since it would have recent improvements in the package. It is a free application so you should be able to get them with less hassle.
In case you have not installed Rufus in your computer, you can feel free to go through the web and look for distribution sites for it. After which, you can insert the Flash Drive and find the Rufus application to launch. To be able to run the software, you would need to ensure that you have administrative rights on your computer.
RUFUS ISO IMAGE EXTRACTION DOWNLOAD INSTALL
To install create a USB Drive with Rufus, you can follow the steps below.