Pushing user input numbers into a 2D Array to form 4 columns with 3 rows

I'm working on a two part task, where the first part is to create an array of 3 rows and 4 columns and then have the user input 4 numbers to make up the first column of the first row. so if the user inputs 1,2,3,4 then the array should print out: (0 just blank for the second part of the task.

1  2  3  4
0  0  0  0
0  0  0  0

So far this is what I have, but I've only been working with Java for a few days and i'm sure i'm not seeing my error clearly. I would really appreciate any help in what i am doing wrong.

Here is my code:

import java.util.Scanner;

public class multipleElements {
    public static void main(String[] args) {
        //set up the array and assign variable name and table size
        int[][] startNum = new int[3][4];

        //set user input variable for the array
        Scanner userInput = new Scanner(System.in);
        for (int i = 0; i < startNum.length; i++) {
            //get user input
            System.out.print("please enter your value: ");

            //push into the array
            String inputValue = userInput.nextInt();
            startNum[i][0] = inputValue;
            startNum[i][0] = userInput
        }
    }
}

as for the second part of the task, the second and third row need to be multiples of whatever number is entered into the first row of that column. So it would look like this:

1  2  3  4
2  4  6  8
3  6  9  12

I'm not yet sure how i'm going to do that so any advice on where i could start researching or what i should look into would also be appreciated.

Please try this code:

public static void main(String[] args) {
    //set up the array and assign variable name and table size
    int[][] startNum = new int[3][4];

    //set user input variable for the array
    Scanner userInput = new Scanner(System.in);

    for (int i = 0; i < startNum[0].length; i++) {
        System.out.print("please enter your value: ");
        int inputValue = userInput.nextInt();
        startNum[0][i] = inputValue;
    }

    for (int i = 1; i < startNum.length; i++) {
        for (int j = 0; j < startNum[0].length; j++) {
            startNum[i][j] = (i + 1) * startNum[0][j];
        }
    }
}

In the first loop you are getting the values from user and setting first row of 2d array.

In the second for loops(2 fors) you are setting the values for 2nd and 3rd loop for each column from first row. That's why first for loop is starting from i=1 and second for loop is starting from j=1.

for (int i = 0; i < startNum[0].length; i++) {
    // get user input
    System.out.print("please enter your value: ");

    // push into the array
    int inputValue = userInput.nextInt(); // <-- assign to an int value
    // assigns the user input to the columns of 0th row
    startNum[0][i] = inputValue; 

    //startNum[i][0] = userInput // <-- not required
}

for (int i = 1; i < startNum.length; i++) {
    for (int j = 0; j < startNum[0].length; j++) {
        // starting from 1st row calculate the values for all the rows
        // for a column and then move on to next column once finished
        startNum[i][j] = startNum[0][j] * (i + 1); 
    }
}