An example of how to perform Isometric game in Construct 2.
Programmer3000: As mentioned in the game instructions (? icon on top of the game):
Numeric keypad 8 : go up
Numeric keypad 6 : go right
Numeric keypad 4 : go left
Numeric keypad 2 : go down
Numeric keypad 7, 9, 1, 3 : diagonals
At worst, check the videos it is explained in those as well.