As long as you're connected to PSN when loading the game, you'll have the option of doing a Daily Challenge. A daily challenge is a random mission with objectives, basically a leaderboard opportunity for players. You can only complete these once per day. To see if you're connected to PSN, look at the top left of the main menu screen. You'll notice a wifi looking icon. If it's red, tap it so you can connect to PSN. If it's orange, it means you're connected.