lambda calculus reduction: (((lambda f (lambda x (f x))) (lambda y (* y y))) 12)


given the input

(((lambda f (lambda x (f x))) (lambda y (* y y))) 12)

what does this step evaluate to: lambda x (f x)

I am trying to evaluate this and I have the following tree so far:

enter image description here

how do I evaluate this ? looking for guidance on what I might be doing wrong or how to proceed with this.