The GPS data are in GPX files format. This is a standard format for exchanging GPS data.
The files can be downloaded in MapSource, OziExplorer, Basecamp and other GPS management applications. The files must be stored on a computer and unpacked. Use the file format your GPS can use. Some of the zip files contain a LesMeg.txt file with brief information on the use and installation of the files.
Be aware that coastal outline may be simplified in these files. This is done not to use up memory in standard GPSs.
Internet Explorer can work poorly for download, use, for example. Google Crome.