I think you have to do it at midnight and dress up in a robber costume then sneak in. Or
try clicking on an item you want to steal. Like say the toilet for example and you click
on it and it gives you a list of choices you can do with it. There might be a "steal"
button in one of those choices

but when i move the curser over the house i cant see the inside. do i have to look through
the window maybe?

Im not really sure about that but you could try.

i usually just teleport in there and swipe somthing with my kleptomatic sim but without
cheats i have no clue whatsoever!!!!

My advice pause the game with start press and hold L1 L2 R1R2 and press yes and you hold
L1 and hit X and you can teleport just look in an window hit teleport in the house when in
click L3 and L1 X on your sim Make Him/Her a kleptomatic and swipe Your Welcome.

i think u have to be in crimanal career and get to like level 5 then at midnight strike
the steal!