Decide your heat target: for near-mild, choose Anaheim or Padron; for a little more heat, choose poblano.
Match the cut to the method: keep peppers whole/sliced small for fast blistering, and roast/peel first for deeper flavor.
Use the listed ratio. If your substitute is hotter, start at half the amount and scale up only if needed.
Cook in a hot dry pan or roasting tray until you see blistering and softening (avoid long simmering).
Taste after blistering: add salt/acid (a squeeze of lemon or vinegar) to balance any extra bitterness.