#1 I need to be 100% certain you can add the Amazon Video app before purchasing this set?
Yes you can get amazon video app. You just sign in and it sends a verification code to your phone and you just follow the instructions.
#2 Please can anyone tell me how to access the settings menu as need to adjust colour and see if i can improve the sound. Thank you.I am an older person
Try going to the home screen where there are icons for Netflix etc at the bottom. Go to the very left icon and press the up arrow and different options should be displayed. I am not at home right now, but I am sure that is how did it.