Enable Manual Cron

Hi there,

If I understood well, with manual cron the email are sent "when users visit your front-end component pages. "

I have 2 questions:

1. how many users should visit front-end component pages to trigger the email?

2. in CjLib Option - Cron configuration I see: Cron Secret Key: is that the license key? Should I put just this key or the whole Cron Url with the key at the end of it? Therefore: what's the Cron Secret Key?

Thanks.