Suppose I have an input sequence like : x[n] = { x0,x1,x2,x3 }.

I have to calculate the DWT level 2:

                  W2 = { S(2,0) , T(2,0) , T(1,0) , T(1,1) }

Where S(m,n) is an approximation coefficient and T(m,n) is a wavelet
coefficient;
m is related to the scale and n is related to the localization.

Can anyone suggest me a link or tell what exactly are the equations
that I should use to perform such calculation? I would appreciate a
webpage with some practical examples. I've been searching for that but
couldn't find none right to the point.

I also would like to know how to calculate the reconstructed version
x'[n] from W2, using the pyramid algorithm. I am not asking for anyone
to do the calculations to me, but just to point what are the equations
that I should use.

Thank you very much.