I am trying to make Alam clock

Hello I am trying to make an alarm clock using time input widget and rtc
but don’t know where to start
Any recommendations
Also I want to play some music as alarm can I fetch music from a site

I have Arduino promini connected to esp-01 module

well, you have worked out that you need a time input and RTC, so you have actually started!

When the actual time is greater than the input time, then it is time to have the alarm.
Once you get that working you will realize you also need an OFF button.

The Blynk sound player widget, does not play sounds. You will have to find some way of attaching your own sound player, and there are numerous products and examples of that in Arduino land.

Can I fetch music from some site

technically yes, but you need to have something to play the music first, then worry how you feed the music to it. You could fetch it using http.