Our desktop programs use the Adobe Air cross-platform installer which needs to be installed on your computer. You can download this from www.getadobe.com
Once you have installed Adobe Air, you can download the program (e.g. alco.air), double click on it and follow the intalller's instructions.
First you need to enable your device to install applications from unknown sources. This is usually found in Settings > Applications or Settings > Security.
Click on the link you have been given to download the file, navigate to the Downloads folder and click on the application (e.g.alco.apk) to install the app.
Your pre-installed downloads viewer may not recognise your download as an application - it won't display the icon and will treat the app as a folder. If this happens, try installing a file explorer such as ES File Explorer
Just navigate to the URL that you have been given to use these applications. You will, of course, have to have an Internet connection. You can put an icon on your home screen. This is usually done throught the bookmarks menu.