Please help me with my simple problem,

1 command button + 1 textbox + values in A1:below

i just want the value in A1 be in the textbox and after pressing the button, next value that i want to appear in my textbox is A2, press again the button and value in textbox change to A3, then A4, A5, A6 and so on until no value found in A column

sorry i just can't understand/know the logic of this as a i'm only a beginner