Im converting to dcc

Hello, its me again. Today, i went on whalters.com in search of a dcc decoder. A syou know, i got a bachmann e-z command for my birhtday. But i am confused on how i convert my dc engines to dcc. The walthers company called me and explaned what i nedd, but i dont know how i would hook it up correctly. I foud the bachmann chip i need, but i have two athearn burlington northerns. And i cant even get off the hoods to put in a chip. So i guess ill just have to buy dcc ready locomotives. I hopefully will get to the hobby store today. Please leave comments suggesting what i should do or how. Thanks!!!