I can't understand ..where to put open braces{ and closed braces in these given coding and why we put i=2 and at last i==num

Question

#include<stdio.h>
int main()
{
int num,i;
printf("Enter the number\n");
scanf("%d",&num);

i=2;
while(i<=num-1)
{
if(num%i==0)
{
printf("this is not a PM");
break;
}
i++;
}
if(i==num)
printf("prime number\n");
}

Answer 1

i find it easier to use indentation as well.
https://code.sololearn.com/ciNBO5hV4s8R/?ref=app