you have to turn it off first, then plug it into a laptop or type c headphones , then the power and volume up buttons, mine also works by using the charger as well, I think its since the update, hope this helps
Thank you for your comment. That is so silly to do it a laptop sort of thing. Before didn't have to do it but now do? I think it is the update. Do you think Samsung knows about this? Going to be a hassle when you don't have a laptop etc. when you really need it. It worked with the laptop, but silly. Thank you for your help.