The pose magnets fit for V4 is simple to use but not intuitive.  It is meant to better fit conforming clothes especially to eliminate pokethru.  Load V4, load her clothing and conform as usual.  Next, while the clothing is still selected, load her magnets from the Pose category of the library.  If pokethrus were prominent after conforming, then they should be gone with the magnets applied.  Underlying problem that can occur, clothing morphs not matching present body morphs.

However, in your case, those magnets would not solve the sitting position with skirt problem.  You would get the best results with dynamics, and I do believe that the manual does cover this very topic you are trying to learn.