How to go from zero to Spartan

I’ve got one of those crazy friends who is about to sign me up for Spartan. I’m in average shape at best, not anywhere near enough to endure an OCR.

There are a lot of posts here about people about to run their first race, but where do I go to learn about everything.

I’m talking about shoes and socks, how to train, whether I can wear sunglasses, Bluetooth headphones, etc.

I’m just overwhelmed thinking about it.

Oh also, I’m pretty broke, so joining a Ninja Warrior gym is out of the question; I’ve checked my local school, and they don’t have good monkey bars. (I do have a pullup bar, at least).

Where do I even begin? Should I take a cold shower fully clothed and then go running while carrying a kettlebell?