How to input data in multi row into datagridview

ALright,here is the detail..

I have a table of datagridview,the thing is I want to put a lot of data into my datagridview. So I write the code(below). when i run it,it's okay. everything is fine. when I type data into a textbox and I hit a save button,the data shows into the first row of my datagridview. It's still fine.

Here's the problem,when I type a different data into a textbox and I hit a save button,the data just cover the previous data(it's mean it shows into the first row ),I just have no idea how to put the data into my second row,so my first data still in the first row... 

Oh Yeah.. Thanks to responde anyway..

Here is my latest code..

 int  j = 0, k = 0, l = 1;
           
            if (txtKodeBukuStock.Text != "" && txtJudulBukuStock.Text != "" && txtPengarangStock.Text != "" 
                && txtPenerbitStock.Text != "" && txtTahunTerbitStock.Text != "" && txtJlhBukuStock.Text != "")
            {
               
                dataGridView1[k, j ].Value = txtKodeBukuStock.Text;
                dataGridView1[k = k + l, j ].Value = txtJudulBukuStock.Text;
                dataGridView1[k = k + l, j ].Value = txtPengarangStock.Text;
                dataGridView1[k = k + l, j ].Value = txtPenerbitStock.Text;
                dataGridView1[k = k + l, j ].Value = txtTahunTerbitStock.Text;
                dataGridView1[k = k + l, j ].Value = txtJlhBukuStock.Text;
               
               
               
            }
            else
            {
                //menampilkan messageBox
                MessageBox.Show("Isi textBox terlebih dahulu", "Error");
            }