Open to the gentle piano page for Hot Cross Buns and press F1 this will give you the key guide on how to do anything you need to do. To change the program to do re me pictures you press I for Italian solfege. ( I am pretty sure) press R to practice with the right hand only, L to practice the left hand only and P for both hands together. Print out the screen shot on F1 and stick it to the wall behind the piano till you get them all sorted in your brain

as to the fingering you let them press with any finger or their nose ( see I remembered!) until the time on the bottom right is lower than the total number of notes on the left. Familiarity first then fingering. Also the finger excersizes, Hannon, black cats ECG help with fingering so practice those too. Once you get to the point where you need to know the fingering there are some lovely videos posted on the forum and I am sure someone will give you the link