How do I use texture maps in Cycles nodes? What I did:


Change render engine to Cycles
Add Suzanne
Add plane
Scale plane by 5
Change environment texture to HDRI from https://hdrihaven.com/
Change Suzanna node setup
Change plane node setup (use default principled BSDF, add image textures for diff (diffuse), spec (specular), rough (roughness), normal, disp (displacement))
Change all image textures to non-color data except for diff (diffuse) and normal


The specific texture for the plane is https://texturehaven.com/tex/?c=wood&amp;t=rough_wood. I am given the option to download:


Diffuse
AO (unused)
Bump (unused)
Displacement
Normal
Roughness
Specular


Is this the correct node setup to use the texture and how do I connect the unused textures?

I am using Blender 2.82a. The wood plane looks flat to me even though I added the normal and displacement nodes.

Nodes:



Render:
There are some things you missed :).

Maps to use:


Diffuse. Plug into Base Color input.
Roughness. Plug into Roughness input.
Normal. Use with Normal Map node and plug into Normal input. Select UV map to use.
Displacement. Use with Displacement node and plug into Displacement input.  


You need to enable material displacement through Options > Displacement > Displacement and Bump (works only in Cycles)
Only works if your geometry is subdivided.  






Bump. Don't use here, since you have a Normal map (which works better)
Specular. Don't use here. (It's more complicated, but I won't address that here)
Ambient Occlusion (AO). Don't use with Cycles, use with Eevee.