EA or advise to run 2 scripts at particular time of the day

I have two (2) scripts that I run 4 times a day. Now I perform the task manually. How should I implement the following task? 
//
When time is 20.00 UTC run script_A;
When time is 20.20UTC run script_B;
When time is 21.00 UTC run script_A;
When time is 21.20UTC run script_B;
//

1.Should I create an EA ? 

2. What is the function that returns the time?  3.Does it return the time of my terminal or the UTC time?

4. From where should I call this function?  From the OnTick() function?