Please read the other answers and comments, there’s a lot more information stated and nuances described (hash functions?) that I did not know when I answered this question.
According to Jenkins’ own help (the “?” button) for the schedule task, 5 fields are specified:
This field follows the syntax of cron (with minor differences). Specifically, each line consists of 5 fields separated by TAB or whitespace:
MINUTE HOUR DOM MONTH DOW
I just tried to get a job to launch at 4:42PM (my approximate local time) and it worked with the following, though it took about 30 extra seconds:
42 16 * * *
If you want multiple times, I think the following should work:
0 16,18,20,22 * * *
for 4, 6, 8, and 10 o’clock PM every day.