Stopper - Cover combo setups

[CharlieTZR]

I've been using since FM22 only Defend with my two CDs; With FM22 I sometimes used stopper/cover but I stopped completely with FM23 since I didn't get a very good grasp on uderstading on trap inside/trap outside and drop off/step up. It works but I can't say I completely understand what I am doing

However now I started a save where I have a great pair of cover/stopper coming from academy and I am thinking to try to use the central pair in this way so can somebody summarize what defensive setups I should avoid ? previously I didn't use this type of combo with offside trap.