A proviso: If scene is too complex, Poser may struggle to trash-clear textures etc. And getting your graphics card(s) to play nice can be a struggle. CPU-only renders are a safe, first step. Just don't set both progressive and branched path rendering unless intended... . Also, an 'Oops': if imported set has opaque walls, ceiling etc, Poser's 'studio' lights may be outside, so scene correctly renders black. You may have to groan then move lights 'inside'. I'm learning how to make imported scenes' 'model' lights --fluo'-strips, wall sconces, pendants, desk-lights etc-- glow via 'super-ambient', warily masked to 'naturally' illuminate the set. Often takes some iteration plus lonnnng ray-traced renders but, IMHO, worth the trouble.. .

May I suggest you try simple scenes with just a Poser figure or prop-object stood on ground-plane ? Move the lights about, do a few Superfly test-renders with eg a dozen pixel-samples, progressive. They'll be speckled, yes, but will give you a handle on the work-flow.

Mind the number of retained test-renders does not overflow Poser's 'cache'....

FWIW, I've the inverse problem to you-- I find DS' UI and work-flow as opaque as Blender's. eg DS' unfriendliness to 'Drag & Drop' import makes me squirm...