I am using membership and marketpress with the affiliate

I am using membership and marketpress with the affiliate plugin and I need recurring commissions for the membership however I do have the code but I don't know what is meant when it says to put the define code in the configure.php file what and where is that?

I also want to put marketpress products at a 75% commission. it says directory not installed but marketpress it says it is. how do I get that directory, and put 75% commission and where to put the recurring code? where is the php file where do I put this? then I will be complete.
leah