[racket] Find nth term of a List

I need to make a function that finds the nth term of a list
Hence (getNth N LS)


Examples of use:
(getNth 0 '(a b c))             ==> a
(getNth 3 '(a b c d e))         ==> d
(getNth 3 '(a b c))             ==> error

so far I have

(define getNth (lambda (N LS)
                   (if (eq? N 0)(car LS)

which only includes the "base case". I need help on how to create this function. Any ideas?
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