How to access the heart rate sensor on my Fitness Tracker?

Question

I have an E66 fitness tracker and health watch that has a real time heart rate and temperature sensor. The watch only records heart rate data at intervals from 10 mins and upwards with the default Android app. However ive discovered that the heart rate sensor is also picked up by two Third-Party apps Strava and Samsung Health that display results every second. I will like to write my own Android app and later on a Windows App to read the heart rate data and display dynamic graphs along with other analysis tools. Ive been through the Bluetooth documentation for Android but they mention that both the Server and client must make use of the same UUID. I can get the watch BluetoothDevice using its MAC address. Now the problem is to initiate the connection as it requires the UUID. Either Strava and Samsung App are using a completely different approach altogether to connect to the watch or they know the UUID. Any suggestions will be appreciated.