When on the login screen, click on the " Reset" button/text under the "Sign in" button. Please see the picture below for a reference of what you should be looking for:
You will then be asked to enter in your cellphone no. you signed up with.
You will then be sent a One Time Pin which you will need to use to verify your account. Once you have verified it is you then you will be able to reset your password.
Once you have set a new password you can login with your new password via the login screen.