The image shows that you have set velocity every frame, which will enable constant movement. That is good.
What I recommend, is to break up your states into many small ones until your better at coding. This way you can visually debug your code and see where things are not working.
So for example, you should have 2 states for movement
State1
Get button "A" down. If button A is down, goto transition "Finished", where Finished is linked to State2
State 2
Set Velocity, every frame.
Get button "A" up. If button A is up, goto transition "Finished', where Finished is linked to State1
This will make it everytime you press and hold A, movement will happen. When you release, movement will stop.