how to change between animations with pressing buttons

hello together

I have a problem when I want to change from one animation to another. In my case there is a character which is walking all the time. Now I want to change from the walking-animation to the slide-animation with pressing the down arrow button. I have also a script but my character still walkes and doesn't change to the slide-animation when i press space (in the script it's space but I'd prefer the arrow down button, but don't know which name I have to use for the button in the script). I don't know exactly where the mistake is that nothing happens with my animations, could also be in the parameters in the animator. So for this you'll find a screenshot of the script and the animator. And if my script is totally wrong could someone please help me by creating another one or send me a valid one.

Hope somebody can help me :)

[1]: /storage/temp/55769-rutschen.png