Looking for help setting up a macro in Synapse 3 beta

So, I've been attempting to set up a specific macro on and off for a few days now and can't seem to get the result I'm looking for.

What I've trying to set up is a macro where I press and hold mouse4, and it presses H once, the moment I release mouse4 from being held down, I want the macro to press H again, but, I cant get it to work for the life of me.

Any support is welcome, thanks.