There are other possible configurations options, but this may be the easiest way to get there:

https://cdn.eventideaudio.com/manuals/h90/1.9.7/content/setup/wet-dry.html

Just below [3.4.1], you’ll see how the Insert is tapped before either of the H90 effects.  Input 1 feeds everything.  Out 3 is used as a send for “without” (no return needed to In 3).  Out 1 will be your “with”.