Post excerpt length

Hello,

I posted here earlier in the week and wanted help creating a grid layout – and you logged into my WordPress and created the grid layout that I wanted, on a test page.

What I want to know is, how do I change the amount of text that shows up underneath each post on the test grid layout you made for me? At the moment any text that I write in the post, shows up in it’s entirety on the main page. If you go to the test layout you just made for me (http://www.thevisualbloq.com/blog-example/) you’ll see the ‘test’ text that I have wrote in the featured post – rather than having all of this text show up, how do I make it so that only three lines of this text shows up, making it so that to read the rest of the text you will have to click through to the actual post?

I’ve tried changing the excerpt length on the theme options but this doesn’t change anything?