You can't make sense of CBMP until you have got the hang of CBM, because CBMP is:
"The placing of the stepping foot, forward or back, onto or across the line of the other foot, giving the appearance of CBM having been used, but without turning the body."
This ought to be obvious enough, but CBMP is regularly used at the same time as CBM (which might appear to be a contradiction in terms, but isn't), and you need a good teacher to demonstrate and explain what is going on, and much more importantly, why.