@ronludington The thing is you need both the watch and the phone. The phone will have Samsung's 'Health' app, and also their cardio app...forget what it's called by it has the ruddy orange and bluish circle with the ECG squiggle in it. To calibrate, open the app, and have your watch on Bluetooth. The phone will also have the 'Wear' app for the watch and for earbuds, etc. If you open the app on your watch first, it will just ask you to calibrate it first. So, with the Health app open on your phone, Bluetooth between the two devices active, and a cuff on your opposite arm, opposite from the wrist with the watch, you activate the cuff three times and record all three sets of readings in the fields in the app. It's very straightforward and obvious when you go through it, takes maybe five minutes in all. Once the app accepts the three readgins, it says you're all set and you are good for about 28 days.

Note that, to keep costs down, you can look for refurbished watches if Samsung USA has them, or look on amazon and other sites for older Galaxies all the way back to V. 4, which is what I'm (still) wearing. I also have a 6, but 8 is out already, probably 9 in September, but they just keep rising in price. I'll bet you can find a V5 for maybe USD$200 or even less...new in box.