hi there

I am now stuck in final fansy 15 playing on my ps4. im stuck on the boss figt for levitan so what is the best way of taking him down?
and what about this how do i change my weapons in the game and use the elixers ? and additianl question is how to get the royal arm and an armor so he its not that hard fighting the boss here.

hopeu can help me out guys

Thank you