How to reduce the excerpt post length

So, I see excerpt blog post's are automatically active in the theme, but I've tried finding in the "code" the setting for adjusting the "length" of the excerpt, but I can't find it.

It seems I've found the spot, but I don't see what I should change, because I see no current # for character length etc., per instructions I've found on the net of what it's supposed to look like.

Bascially I need the post to be about HALF the size it is. It's too big for excerpt listing.

What file is the code in and what does it look like?
Thanks

Never mind, answered my own question. For some reason when I searched "excerpt" yesterday it only game me two posts, but I found the one I need now.

It is an option "Length of content in the feed" on page Dashboard -> Theme -> Layout in the dashboard of your theme.