Work for Japanese convinience store

I had a job interview convinience store.
I felt things went well, I will wait they contact me soon.

I never worked in Something using cash register, I would like to know if it is simple or hard?

Anyone had experienced please comment.

It's easy once you get the hang on it, they will show you how to use their systems etc. You will probably have to do other things besides cash register like making bento boxes, easy fry cooking, dealing with payment of customer bills and packages.
It's quite a busy job, you'll normally have something to do.
Convenience stores are normally good with hiring foreigners and making sure they attend to their needs with language barriers etc

of course, convenience store owners want to hire Japanese at first, because major customers are still Japanese. hiring foreigners is the second choice.
I think cashiers at supermarkets are more easy than those at inconvenience stores, because the latter work is too vast.
convenience stores deal with tax payment, shopping payment, concert payment, etc. takuhai-bin (you have to know which one is acceptable, how to calculate the fee, what is inhibited, etc.), and cash-less payments (which one is usable, and not, so many.) their work is enormous and ridiculous.

Do not worry to much about that. Because, they will teach you how to work in each aspect of the working in convenience store. The customers will help to to practice time by time. Learn how to do reji-tenken (counting money in the cashiering), takuhaibin (sending packages), tobaco okiba (place where you will put the tobacco; learning the names in Japanese), haiki (throwing the expired products), usage of cooking and making coffee. These all can make your working abilities like a Japanese or experience foreigner worker.