How to open the blood oxygen test of Apple Watch?

After purchasing iwatch, I want to use my watch to measure blood oxygen data. I don't know where to turn on the function, so how to turn on the blood oxygen test of Apple Watch?

How to open the blood oxygen test of Apple Watch? 1. Open the watch app and click on blood oxygen.

2. Turn on the right switch of blood oxygen measurement on the blood oxygen page.

This article is based on Apple Watch 6 &；; & such as IPhone 12, suitable for watchos 7&; & ampIos 14 system