Integrating apple IAP

I've been searching around for a few days now for an up to date in app purchasing tutorial for iOS. I've tried the one on the unity site a few times but doesn't work for me, (the purchaser scripts they ask you to add creates errors). I've also tried this one on YT https://www.youtube.com/watch?v=zsWVcAajMjY but it uses Soomla, which is no longer supported to my knowledge. All other tutorial that I can find are for android. If anyone has any advice or can link me any tutorials that they know of that would be great, thanks!