Hello,
I want create my first app - simply app, that can work with watch sensors. Simply app, where I can set low and high limit of heart beat and if this limit overflow, it will send notification or alarm. For example something like monitoring for old people (but this is just 1 of 10 thing what I can measure). This app should be able to send sms notification (we are working with LTE) and should be updated remotely (if new version or some updates appear).
I know a lot html, css, php, sql, javascript - but I’am new in mobile app. Is there any change to create this app using this languages or I should start develop this app directly in .NET, C# or… ?
Do you have / know any simply samples / demo how to work with watch sensors and show on screen actual beat rate and others? 
Thanks for any advice