The owner should tell you how often to feed, if its a baby corn usually every 5 days, once feeding on 2 fluffs then you should feed every 7 days and once on medium it should be every 10 days,
As for cleaning, if on wood chip then spot cleaning every couple of days or when you see poo, a full clean every 2-3 weeks,
if on paper or tissue then clean out every 3-5 days if there is poo around.
Corns hand be handled on a regular basis as this allows then to be human friendly and not aggressive when you enter the viv, so you can handle for 5 - 10 mins to start then increase time, (again ask owner how often they handle, but remember not to handle for 48 hrs after feeding,
Apart from that as long as temps are correct and the snake has plenty of water then it will be ok.