My b2evolution Version: Not Entered

I searched through all the settings in b2evolution and did a search in the forum, but didn't see an answer. It's probably an easy solution, but I'm new to b2evolution & using blog software in general =).

I don't want to display the entire text of a post, how can I truncate every post to say, 15 lines, and then display something like a "Read More" link?

Thanks in advance!