Q1:Inaccurate measurements for heart rate.

1)Make sure the sensor underneath the watch is clean and has good contact with your skin.
2)Stay calm during the measurement for better accuracy.

Q2:Inaccurate step count.

The watch actually monitors the swinging of your wrist in order to register the step count. If your arm is mostly in static positions while you go about your daily activities, then the step count may not be registered during those moments.

Q3:Watch fails to receive notifications from smartphone.

1)Open the iPhone's "Settings" app, then tap on "TINWOO" on the list below.
2)Toggle on "Notifications". If it is already on, turn it off, then on again.

Make sure pop up notifications are enabled for the apps you wish to monitor on the watch. Apps that have their pop-up notifications disabled may not get those alerts on the watch.
Also, for the notifications to keep coming in, the watch needs to stay connected to the app.

Q4:The watch keeps disconnecting from the smartphone.

Do not swipe away the app. Check the permission settings on your smartphone. Make sure the app is allowed to run in the background.
Connectivity will be lost each time your phone automatically stops the app's background services from running.
Also, make sure your phone's Bluetooth stays on while the app is running.