Click the green flag. Wait until the small black dot says "Ready", then click to the top, bottom, left or right of the sprite. You must be within 10 pixels of directly in the direction, or the program will not recognise the gesture.
I coded this myself but used inspiration from a few other, similar projects. I was stuck at the beginning, as I couldn't get the DIRECTION right. I then changed it to respond based on the RELATIVE POSITION. This is meant to be remixed and put into another project, so I made it as simple as possible.