Some of the delivery jobs posted near you come with a notification. The Offers page and the notifications work from two different addresses: the page follows where your phone is, and the notifications go by the address on your profile. If you moved, open the menu, tap your name, and update the Address field.
Push notifications are how you hear about new jobs as they're posted. The Offers page shows a banner for this, "Want to know when jobs get posted?", and one tap sets it.
As you use the app more often, you'll hear about more new jobs. Opening it most days keeps the notifications coming through the day.
One notification needs an answer. If you applied to a job hours ago, a push can arrive asking you to confirm you still want it. Open it and tap Accept, or the delivery goes to someone else.