Omnigraffle - how to make double ended arrows?

I'm learning Omnigraffle and am ok with most shapes. But I want arrows with heads at each end, like this (done in Pages.app):

I'd also like to know how to put the tips of the arrows where I want, rather than Omnigraffle's default which is to attach a line to a corner:, like this:

Following Dave Delong's answer below, I realized that you have to style each end of the line.

Like so:

1. Select the line (or lines) in your OmniGraffle document
2. Open the Style Inspector (Inspectors Menu ▸ Styles, or ⌘-1)

3. Select the second style inspector ("Lines and Shapes")

   

4. Use the popup menus to choose an arrow style