Never played competitive pokemon myself either, but after my first run in reborn i started training EVs on my pokemons, First run i beat her with my simipour with surf , she would usually start with eruption on typhlosion which would turn the field into burning and surf would do normal damage and get it back to super-heated, so i would just spam surf on simipour and use the others pokemon to heal simipour when needed.
On my second 2 , using EV training , i managed to eliminate the field with a Frost Rotom with blizzard on first run, with EV traning he was able to outspeed her pokemons ,withou
