I suspect there is a missing menu link.
Can someone tell me if I'm missing something?
Drupal 8 panels and panelizer is very different than you are used to in Drupal 7. There are no global configuration pages under the structure menu. To panelize a content type you go the manage display tab of the content type you want to panelize. From there, you have a checkbox called panelize this display. Once you check that option you get the panelizer configuration options. As far as managing blocks etc inside of layouts, you use IPE from the node view. I much prefer the Drupal 7 way but once you get used it you find that works OK.