To download GNSS data from Emlid Reach you need to make the following steps.
Install GNSS antenna to drone, put drone to open sky view, turn Teodrone on and after a few minutes, web-interface of Reach will be available. Be sure, that at least 6 satellites are available to the drone.
Turn on Wi-Fi on your PC and connect to the network "reach-XXXX" with the password "emlidreach". Type http://192.168.42.1 in browser and get into the web app of Reach.
Go to the Logging page. You'll see the list of all ubx files. Date and a time UTC in the file-names mean the start of the GNSS-data recording. For example, the filename "raw_201911050455.ubx" means that the begining of GNSS data recording was on November 05, 2019 at 04:55 a.m., UTC.
Download the files into your PC and Unzip them.