Conditions are tested until one is found that is true, the associated statement is evaluated, and the COND is exited.

(COND
    ((test_one) (do_this_1))
    ((test_two) (do_this_2))
    (T (do_this_if_nothing_else))
)

The do_this's can contain multiple statements:

(COND
    ((test_one) (do_this_1a) (do_this_1b) (do_this_1c))
    ((test_two) (do_this_2))
    (T (do_this_if_nothing_else))
)