You are downloading the BigBig Elderly Desktop XAP file v2015.1.24.1 for Windows Phone. BigBig Elderly Desktop is a free Kids & Family App: This is a software for the elderly, big font size is the main feature. Please pin this application to the start screen. You can now download the offline XAP package file to install & try it.
Download Locations for BigBig Elderly Desktop 2015.1.24.1 XAP file
To try to install it manually from an SD card, you should choose one of the server location above to get the offline BigBig Elderly Desktop XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.