You cut out the appropriate chunk from the new filter. Cover the accelerator pump bump and surrounding areas with vaseline or some other release agent, then glop RTV onto both the filter and the accelerator pump, then mount the filter. While it is curing, maybe you add a little more RTV to the outside if you left it thin in spots, maybe you just shape it a little with a gloved finger.
Once it dries, you pull it apart and fill or trim the "inside" if necessary.
Let it cure, then reinstall and go fly.