the website itself is pretty easy to use. You can use google translate. But to buy coins you're going to need to download the app. This is where i messed up because i couldn't translate and rented the chapters instead of buying them. So i suggest you buy the coins on the app and then buy the chapters on the website
If you don't mind I wanna post http://www.mrblue.com/section_webtoon/detail.asp?pid=wt_blossom_wz for the raws. It's the non-mobile site and was much easier to use. And it takes paypal yay! Take that lezhin!
http://m.mrblue.com/webtoon/detail.asp?pid=wt_blossom_wz
If you're going to buy the raws, make sure you purchase them. I accidentally rented all the chapters instead of buying them. Unless you want to rent them, then, by all means, go ahead.