In Drupal 7 I would use Display Suites to create custom layouts for display modes. For example I could create a teaser with two columns and place fields in whichever column I wanted.
I am pretty sure that this is possible in BackdropCMS, but I can not figure out how to do it. I am not sure if it can be done with Backdrop core or if it involves a contrib module? Or maybe, it is not possible at all without a custom template?
Can anyone point me in the right direction?
Actually, it's not. Yet! Long term, we would like to replace the "Manage displays" interface with something that looks more like Layouts and allows you to drag/drop fields around, but for now the only way to achieve this is to use a node--view-mode.tpl.php file, and hard-code your field placements.