3D surface

Hello, how can I create 3D surface (sine wave) and plote it? Are this correct? x = 2; % Sets the resolution (step length), in µm, along the x-axis. y = 2; % Sets the resolution (step length), in µm, along the y-axis. z = 1; % Sets the resolution (step length), in µm, along the z-axis. xLength = 4000; % Sets the length of the surface in X. yLength = 3000; % Sets the length of the surface in Y. wavelength = 100; f = 3*sin(x*2*pi/wavelength*[1:4000]) + 1003; % The function for the sine wave with the % amplitude 3 µm and wave length of about 100 µm. Mean level is % 1003 µm. I cannot plot this function. Thank you very much