limit display number of listings in tabs elements

Hi there Josh

i am trying to limit the listing in custom tabs & content elements to 8 or even lower.
i tried this code (meta_key=featured&meta_value=yes_posts_per_page=8) but didn’t work, also i contacted the live support to reach out if i can get help, but no not really, altough this one of your operator has helped my me out previously but today he or she might have been very tired working at night.

Appreciated