I could see the AUR repository and search it, yet install always failed. From another post, I found the default directory was /var/tmp/"username". I created the directory, sudo mkdir etc. Selected it in the Pamac preferences, and it still failed. Changed owner to my username. Changed mode to 775 so both root and I had full privileges. It worked. I now have the browser plugin for OBS.
Hopefully this will help others who may be having similar problems