how do I open the oil cap?

Hey Babebarb! There's no secret here, you just need to babe up and get a stud to muscle it open. One of the better tools to accomplish this however is a strap-type oil filter wrench (make sure you have knuckle first-aid handy!). If the top of the cap just ratchets however you'll need to pry the top plastic part off with a screwdriver and use a pair of adjustable pliers to get the rest of it unscrewed. Good luck!