Merging gpx files with gpx.studio

The TGO Challenge Coordinators very much appreciate if Challengers provide a single gpx file with each individual day of their route separately identified within it. If you have multiple gpx files, this 3-minute video shows you how you can merge them into one file, whilst keeping the days separate within it.
If you don't know how to download your gpx files from your digital mapping software, there's another video on the TGO Challenge channel covering that.