You cannot directly link a Polar object to Kiplin. You have to use Google Fit for this, it will be like a bridge between the two applications.
Open the Polar app : in Home > Settings > Google Fit, sign in with the same email address registered in Google Fit.
Then, if it’s not already done, in the Kiplin app > Homepage > click on your profile (at the top right of your screen) > unlink my tracker. Link your tracker selecting "I have a connected watch" and follow the steps on your phone.
We cannot guarantee it will work as Polar and Google Fit are not always synchronizing well together. Thank you for your understanding.