Got my first job and I’m nervous!!

Hi so I just got my first job and am extremely nervous! I applied to Jack in the Box as a cashier (the pay at my location is so good) I start on Tuesday and I honestly have never worked a cash register & have no experience so I’m really nervous and scared that I won’t know what to do or that I’ll forget! Is working a register hard at Jack in the Box/any fast food restaurant?? Any tips??