So, I read the appendix in TCOYF that explained how to chart during times when it's difficult. It was pretty quick, and not that helpful. It basically just said look for the
change in cervical mucus. Like, you could have some cervical mucus for 2 weeks, and then all of a sudden it changes. I didn't find the appendix that useful, but I did find this:
http://ccli.org/productsservices/nfp-materials/manuals.phpThey have a manual on charting after postpartum, and it's only $25.
There's also classes that may be in your area:
http://register.ccli.org/classes/search