I do them! You have choices, you can input your data manually, or it can come from your wrist device (mine is Apple Watch) and you can also choose with some if you do the long or shorter challenge. Re the medal, you go through a checkout to get the medal, to make sure the address is correct etc. I’ve got a few medals now, I’ve had some issues with my watch sending date since I switched phone, but since I’m mainly using them now for other things than walking or running I’ve not made a huge effort to rectify that. You can also have several on the go at once. I haven’t done a Harry Potter one, I signed up for the scooby doo one thinking my kids would like it, and honestly it’s rubbish. I’ve much preferred the ones with actual map view you can nosy around, the scooby doo one is just a cartoon background with a line you move along, so I’d maybe try and look at what the potter one is formatted like before signing up as I would be disappointed if it was like the scooby one. The medals are really nice. I had one arrive broken and they just sent out another but it’s just been the one.