The following is a 4 part (almost 3 hour) video presentation by the Ohio ARRL that explains programming DMR code plugs. This is a detailed presentation and will answer a lot of questions. Dale (KC2CBD) of the Putnam County ARES recommended this series to members interested in using DMR.
http://arrl-ohio.org/digital/cp-writing.html
73, KW1LL
White County Amateur Radio Club 