confusing instructions for software purchases

I have found the instruction for software i purchased Avast anti-track but I end up purchasing the same product twice because i click on the tag that says install and activate…I take that as instruction to continue with my purchase but what happened is it charged me twice for the same product…please make instruction a little more understandable for us that are less tech saavy…I requested a refund for the one because i only needed one…