why is my micro card not downloading stuff


Make the right settings. Go to PlayStore(android) settings and make the apps to be downloaded into SD card. If you cant make it... just downlaod and then replace APPs from Phone memory to SD card ( some information will still be at your phone memory... but thats android...)
You can make your camera to save pictures on SD card and all kind of information. Beware that if SD card goes wrong all of your information will be lost.