Which monitor is actually going to work with my Sony FX30 because I honestly have no idea what I am doing and I feel like I am going to mess up my first big shoot.

I just bought the FX30 because everyone said it was the best camera for people starting out but the screen on the back is so tiny and I can barely see if things are in focus or not. Im supposed to film my cousins wedding in like three weeks here in Chicago and I am panicking because I cant see anything when I go outside in the sun. I heard I need an external monitor but when I look online there are so many options like Shinobi or Feelworld or Ninja something?? I dont even know what the difference is or if they come with cables and stuff or if I have to buy those separate.

I only have about $250 or maybe $300 left in my budget after buying the camera and a lens so I cant afford anything super expensive. Do I need one that records or just one that shows the picture? Someone mentioned something about nits for brightness but I dont know how many nits is enough for a sunny day outside. Also does the monitor drain the camera battery or does it have its own? I am really sorry if these are such basic questions I just dont want to ruin the wedding videos because I couldnt see the screen...