Open trailguide.net in your web browser on your phone.
On Android, web-apps are integrated like native apps. The second time you open Trailguide you can click on the "Install" button at the top left and it will be installed. If there is no "Install" button, just add it to your home screen to install it.
On IOS, open trailguide.net in the Safari Browser and add it to your home screen. It will then be installed as an app and also work offline.
Starting Trailguide from the icon on your homescreen it will behave and look like a native app.
What is a web-app?
A web-app has the functionality of a native app, works offline and has access to the device hardware.
But it is easily accessible through the browser, is very small (the size of Trailguide is just 270kB), fast and efficient.
Web-apps combine the advantages of a native app and a website.
A web app cannot be found in the App Store or Play Store.