To access content behind QR codes you have to scan it with your phone using camera and a special software. Software is free and available for almost every modern mobile device. Since there is a lot of QR code applications, best way to get reader software is by visiting http://ma.rs/reader with your mobile browser. When you visit this page best software will be presented to you. To download QR code reader software you must have Internet connection set on your phone.
Mobile Internet settings for mobile operators in Serbia:
After application is installed you can run it and point camera toward QR code. If software supports automatic detection, information from code will show up on a screen, if not you'll have to take a picture and wait for few seconds. After successful scanning, depending on a type of data behind the code, application will present you with options. For example, if site address is behind the code, software will either automatically open browser page or give you the option to do that.
To successful scan smaller qr codes, your phone camera should be able to use focus function.