I need a box to move from a to b to a and loop it

Im new to Unity, but I really cant get a answer to this question.

I have to code this in c#.

I have an object. It is standing on 0, 0, 0.

I just need it to move from x = 0, to x = 10, then I need it to move down a bit. Like from y = 0, to y = 5, then I need x to move back to 0.

Think like the Space Invaders game.

Can someone post a working code so that I can see how its done? As easy and short as possible.