如何在Grid中显示文本框值

i am newbie in extjs , i want to add row in grid when i click a button , my form has three textbox name , id--name--age , and i have a grid with three columns id--name--age , now i want to add value of textbox id in column id , value of textbox name in column name , and value of age in textbox age. now i have no idea how to perform this ,please help me to resolve this , as i have experience in vb.net and c# there is a property of grid called rows.add , in js is there any property like rows.add to add rows in grid.i am newbie in extjs , i want to add row in gri