How do I insert code in my posts?

Inserting code in your posts is likely something that you'll want to do.  Fortunately, this isn't very hard to do.  First, start a new line and where it says --Format-- in your toolbar and select "Preformatted".  Then select your language from the --Styles-- dropdown. THen just start typing your code.  You'll end up with something like the following when you submit your post:

puts 'Hellooooo from Ruby' 

And that should get you what you want.