Read these to get the ideas behind Evans' program. In particular, make sure that you can understand Winston's account, and that you could work an example for Finals by following it.
The chapter on Creativity has a nice four-page account, conveying the essentials without confusing detail. That's pages 319-322 in both first and second editions. Treat it as preliminary reading to Winston.
From the top of page 24 to half way down page 33 starts off with what distinguishes a good representation from a bad one, and then continues with Evans' program. Apart from section 5.3.3 of Evans' own article below, this gives almost all you need to reproduce the workings of Evans' program. One extra point: you should be aware that Winston's account is different from Evans' own, being simplified to make it easier to understand. The program was actually more complex (so it could run faster). However, the principle, of finding the difference between A and B, and then looking for that figure Dn which differs from C in the same way as B differs from A, is the same.