How do I flip character in the opposite direction?

I'm not sure if there is a tutorial on this so I apologise if there is.

I got my character bouncing up and down correctly (idle animation)

If I press on the left arrow key I want my character to face left. How do I do this?

You would use the 'Set Mirrored' action.

I would very much recommend Ashley's - or one of the other - excellent tutorials from the Tutorial section at the top of this page. It will cover everything you need to get going on basic platforming and animation.

You can set event: When left key is pressed ==> Set (Character) width: (the negative of the current width size)

Naji

Mirroring is easier than manually setting the width.

Best is Mirror all you do is set Keyboard keys or mouse key like below

keyboard left keydown = myobject mirror or Mouse button click = Myobject Mirror

system else

myobject = notmirror

Or you can also use an idle animation when left or right arrow is not used

Try and learn from this demo I made for you