There are two ways to share your live signup page(s) with your volunteers. Each event has its own unique link, which you can find under Events > Your Events, just beneath the green (or grey) online/offline toggle button.
If your organization has more than one event, you might consider sharing the public landing page URL instead. This link can be found at the top of the "Your Events" page, or under Account > Settings. The public landing page will display all upcoming, public* events - you can showcase these events in a list-view or as a grid of images.
*To make your events public, go to Events > Your Events > Event Detail and click to “List this event on your public landing page” in the Optional Settings.