Hi Everyone. This Is My First Post On EPforums And I Will Be Telling You How To Run Genesis Games On Your DS Or Your 3DS.
First Of All You Will Need A Flash Cart. For Example R4 Or NDSTwo
You Will Then Need To Download JenesisDS From This Link.

Copy The .NDS File Into Your Flash Cart And The Emulator Should Run.
For The Roms You Have To Create A Folder In The Root Directory And Put Your Roms In It. It Is Best If You Name Your Folder "Genesis" Or "Genesis Roms"

That's All For This Post. Hope I Helped You .