I wouldn’t say it’s particularly complicated, but it does take a little more effort from your end @kelvincorp . Take a look at this thread for a list of middleman services and websites, and this thread for help with search terms and navigation. Both are thorough and very helpful for beginners/people who don’t speak Japanese. Would recommend people give this a shot because it is usually cheaper than eBay for most Japanese promos, boxes etc.
I would start with Buyee because it’s the most user friendly in my opinon. Each middleman service has various pros and cons, but they’re all pretty reliable these days. If you need any fruther help, feel free to message me on here or instagram at the same handle.