Thank you both for the clarification. I will put the 0.78 roms into the Arcade folder. I think there's enough games in that set so that I won't be adding anymore arcade game which is what my main purpose was for putting this unit together. I never really played any console games but I think I will add the top 25 games of all time per console to beef up the unit. Hoping that my 64gb card will hold everything.
Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first