Use Euler’s method to estimate y(1.2) the solution to the IVP (initial value problem) y^i = 2t-y, y(1)=-1 and step size h=0.1

I know I need to use equations like

fo=f(to,yo), y1=yo+foh but I am not sure what is going on with the y(1.2) thanks for any help. (The answer is y(1.2)= ~-0.41)