This is a simple problem really, and you should make the most out of it by trying ... else you will never learn to go at it independently!
As Spuds said, robots are very stupid so you need some "performance metric" you will maximise/minimise while looking for the goal. For example, you can sweep the entire grid by going all the way up, then take a right and another right and then come all the way south etc. until you bump onto the goal. This is a greedy approach though but if there are no other clues it is the best bet.
Can your robot see beyond the current cell?
Does your robot know anything about the grid/environment or it is going blind?
AI tries to simulate human intelligence ... just think how YOU would look for the goal and code it .. it is THAT simple really.