Like Cristopher Oliver said, u can use the nth function.
nth n list
(nth n list) returns the nth element of list, where the car of the list is the ``zeroth'' element. The argument n must be a non-negative integer. If the length of the list is not greater than n, then the result is (), that is, nil. (This is consistent with the idea that the car and cdr of () are each ().) For example:
(nth 0 '(foo bar gack)) => foo
(nth 1 '(foo bar gack)) => bar
(nth 3 '(foo bar gack)) => ()