Plugin installed but I cannot see the effect?

Got this blog here:

http://www.petebellotte.com/and-another-thing/

Which is a summary, but I want the summary to use HTML tags, so instead of post all on one line and want to see carriage returns so text is shown as the post was created.

Have I misunderstood the plugin usage?

Many thanks

https://ww.wp.xz.cn/plugins/advanced-excerpt/