Clone this git repo to your computer
Open a console and prompt it the the "RoutenTool" folder.
Run the command npm install
If nodeJS and/or npmjs isn't installed yet, install them first. On Linux run the command sudo apt install nodejs npm
Prompt the console to the parent folder of "RoutenTool" and run the command node RoutenTool
The console logs the URL and Port over which you can access the Visualizer.
On the first run the program creates a folder called "data" inside the "RoutenTool" folder. Load your .GPX files inside this folder. Reload the side in your browser Now you should see the Tracks embedes in the map.