Depends how primitive it is. I'll camp with my family all the time with no running water or electricity at the site, but there's still bathrooms, running water within walking distance of the site. That, I feel is doable for even folks that haven't really roughed it before. But if you've got to manage water by either bringing a tank with you or purifying stream water, along with no toilets, that's some varsity level camping that you definitely want to look up and make sure you're comfortable with it.
But if you can walk to a toilet and running water, you can get some water holders for your site that you can fill up and carry back. Some camp grounds will even have a camp host that has a small motorized vehicle to help you take water back to your site if a half mile with 40 pounds of water sounds like too much for you.
If you've never cooked on an open flame before, you can get a gas stove and some gas relatively cheap as well and then just cook like you do over your range at home. Make sure your cooler and ice situation is good, especially for three nights. You may need to go to a nearby store and buy more ice for that long. You can also focus on non-cooking food for a few days if all that is intimidating, wouldn't be the worst since it's for a short time to just have some non-perishable, or long term foods like some fruits, jerky, bars, etc.
I would get a small solar charger/battery pack for your electricity needs. Charge it full before you leave and then recharge using the solar panels during the day and that should be good enough for your phone. Get a good LED lantern, preferably one with solar charging on it for walking around at night. I also use an LED string light set with a solar panel on it that I hang on the tent at night for extra light.
