I have been trying to download the programme on my mac book pro. The operating system I have is OS X Yosemite. The programme seems to download but then I can’t use it. Any help or guidance would be very much appreciated. I tried following the instructions given on another post but as I move through the steps I get lost not knowing which icon to click on when choosing to install for a mac, I tried every one but nothing changes, I just keep downloading what appears to be the same thing over and over.