Our house is relatively small and our DSL router is ony about 3 feet from my two office desktops.
But I get very poor wireless speeds on those desktops. (I suspect my wifi adapters are out of date.)
My simple solution was to run a physical ethetnet cable down into the floor, through the unfinished basement and back up into the corner of my office.

That wired connection gets me the best speed.
But I would now like to also physically wire connect a 2nd desktop computer without running an entire 2nd ethernet cable.

I am trying to repurpose an old Amped R10000G router (Router B in the attached) as a ... Hub? (or is it a Switch? I am not clear.). But I cannot figure out the basic or general settings I need to set to make this work.

could someone just sketch it out for me?

If I don't want to use the wifi on Router B, I presume under Wifi settings I just turn Wifi OFF.
But I cannot figure out how to configure the Networking settings.

(Hmmm, I don't seem to see how to post an image here. let me try this: