Double Jump after single jump?

basically i want my character to do a double jump after a single jump but the character to land before the double jump happens. Also i want the engine to check a certain speed before doing the double jump. How would i acheive this?

Have you at least checked out this?

It may help you with your problem. Just make sure you do exactly how he does. Believe me, I followed all the steps from the wall climbing tutorial and it works 95% for me.
If the blueprint in the tutorial doesn’t almost look the same as yours, then please upload the screen shot of your blueprint.