Here’s a site that goes over the basics and discusses how scanning can be useful for close reading: http://server.riverdale.k12.or.us/~bblack/meter.html
Poetry explication handout (w/ scanning hints): http://www.unc.edu/depts/wcweb/handouts/poetry-explication.html
I’m not the only person in the world that thinks a computer program could/should be written that scans poems: http://www.ftrain.com/theory_ideas_giantlangtool.html
Short, sample explication: http://www.uncp.edu/home/canada/work/markport/best/study/explic.htm
Longer, sample explication w/ discussion of meter: http://www.unm.edu/~aobermei/Eng200/samplepapers/assignment2sonnet42/index.html
Hope this helps!