How do you replace a window pane in a dual pane window?

Forgive me, I'm not very window savvy, I'm not sure if our window is double hung or what, it is a vinyl window, bottom part of the window slides up, the top is stationary. The part of the window that slides up has two panes of gl, only one is broken. Is there a way to replace just the one piece of gl instead of spending the money to replace the whole window? I have figured out how to take the window out, I just don't know how to take it apart to get the old gl out and the new gl in. Would appreciate any advice!