as i understand , this question is not related to Construct 2 itself , but it's okay , as an artist , i would tell you many ways to do that , but since and as it is obvious your are not an artist ( obvious because you don't know how to) i would suggest you make pixel art graphic assets , anyone can make pixel-art all you need is your Ms paint software that come with Windows, zoom it to the max and press Ctrl + G to show the grid and just start making your assets , don't worry pixel-art is not ugly , look what i'm working on currently using Ms paint ( i just wanted to try a pixel-art style for my next game)