Please explain to me, I don't understand. what means is a first "for"

Question

import java.util.Scanner;

public class Main {

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int length = scanner.nextInt();
int[] sides = new int[length];
for (int i = 0; i < length; i++) {
sides[i] = scanner.nextInt();
}
for(int t : sides){
System.out.println(t*t);

}

}
}

Answer 1

In the first for-loop we get user input. The user input is filled in the sides array

Answer 2

in your code first 'for()' is
for (int i = 0; i < length; i++) {