BEGINNER HELP

Hello, I live in Austin Texas. I have literally never gardened in my life. I have this weird raised bed in my front yard that has regular grass and is barely fenced in with some metal bars. It’s about a 5 foot long 2 foot wide rectangle shape and I want to put some easy to maintain flowers in it. It’s technically spring time here and the wildflowers seem like my best bet, what do y’all think and how should I start? It is just like my lawn inside the box btw, nothing but dirt and grass.