Lightroom won't show correct photos in album (Mac)

Hi,

I'm having a problem with importing photos from my Mac into Lightroom. I go to 'add photos' and then it brings me to my files. No matter what folder I click on to open, it brings up the same photographs each time. So for example, if I click on folder 'A', it brings up a selection of photos from A. However, if I click on folder 'B' it still brings up the photos from folder A. I'm not sure if it's a trivial issue or if I'm just missing something really obvious!