I'm having trouble setting up a structure. My instructions are

"Define the structure dollarsQuartersDimes
with three simple variables int dollars, int quarters and int dimes
to declare monies in dollars, quarters and dimes.

Write a program to
add two dollarsQuartersDimes monies and store the result in the third dollarsQuartersDimes monies.
Remember to make necessary dime and nickels to quarters and quarters to dollar conversions."

Yes that is word for word from my professor.....a foreign professor that cannot communicate in English should have no business trying to communicate a programming language. Anyways...what I got from the assignment description was this :

-Ask user to input amount of Dollars, Quarters and Dimes
-Add the inputted values to previous values in the structure
-Redisplay the updated values

This is the code I have so far :
Code:
#include <stdio.h>

typedef struct dollarsQuartersDimes_struct {
  int dollars;
  int quarters;
  int dimes;
  
} dollarsQuartersDimes;



int main(void)

{
    
int a;

printf("Enter the amount of dollars, quarters, and dimes to insert, separated by spaces> \n");
scanf("%i %i %i", &a.dollars, &a.quarters, &a.dimes);

a.dollars[3] = (a.dollars[1] + a.dollars[2]);
a.quarters[3] = (a.quarters[1] + a.quarters[2]);
a.dimes[3] = (a.dimes[1] + a.dimes[2]);

printf("You currently have %i Dollars, %i Quarters, and %i Dimes.", a.dollars[3], a.quarters[3], a.dimes[3]);

a.dollars[0] = (a.dollars[3]);
a.quarters[0] = (a.quarters[3]);
a.dimes[0] = (a.dimes[3]);


}
For some reason I feel like I am moving in the wrong direction as I do not think it's possible to set an initial value of a structure. Any suggestions on where to build from?

Thanks.
-Jim