help me to make it

Friends, I am completely new to this world of gadgets or circuits or all that. Simply I want to make a digital wrist watch which should carry these features.
1-It should have an incoming call detector
2-An alaram (Tone would be my own recorded )
3-What any wrist watch provides (time and date)

Do care to share your knowledge.

Welcome to the forum.
I hate to be the bearer of bad news but that would be an extreme challenge even for a very experienced constructor of gadgets .

First, Get a few Engineering Degrees, a Million or so $$$ and a Good Chinese Manufacturer.
Be Prepared to order a LARGE Quantity of them.
No One will make just one.

I admire your desire to make such a device. But, as alec_t notes, a very complex task.

As it is, however, Apple has beat you to it... https://www.apple.com/watch/features/

Take a look here: **broken link removed**

I'm not sure what an "incoming call detector" is.