Max lag length for EG and Johansen test and result analysis?

[kstanza]

I have 2 sets of data, both with the same number of observations. Both are stationary at 1st Difference.

I would liek to know how to work out the max lag to input when performing the EG and Johansen cointegration tests.

and as a side note (as i have never actually been taughr econometrics, but am supposed to do a project on it) what are the significant results in the output data, as there is alot of data given back and im not sure if i need to anaylyse all of it or not.
What do i need to reject the null hypothosis or accept it?