Hi
Under watchOS 4, for Apple Watch Series 1 models, the Heart Rate app will report your resting heart rate once it has gathered sufficient data.
To view your resting rate, open the Heart Rate app and scroll down the page (by swiping or turning the Digital Crown):
Resting rate is also reported in the Health app on your iPhone (Health Data > Heart > Resting Rate:
Use the Health app on your iPhone or iPod touch - Apple Support