Hi everyone, I’m looking for help!

So my friend and I were recently on the phone and he decided to challenge me to to a 50K ultra no I know very minimal about running these days but in high school I ran quite a bit longest distance I ever ran was probably about 12 to 14 miles my running gear was very minimal BOA shorts, Brooks running shoes, plus nike flats for speed Work, and an Apple Watch. In my opinion, I think ultra marathons are a totally different beast compared to 5K’s 8k’s and 10k’s. I know next to nothing about gear and training when it comes to these distances so if anybody could help me out, I’m looking for a very minimal running watch some sturdy running shoes and even better running shorts or running tights. Thanks for your help!