Donald needs you to find a boat and collect six drug packages that will be dropped by a plane off Staunton Island. Each package will increase your wanted level (to a maximum five stars), so considerable law enforcement will be waiting for you on the shore.
The actual collection of the packages is not timed and not difficult, but allowing the police to reach them first will end the mission.
When returning to Love, you can always loop around in the boat or try to find a different spot if there are too many FBI waiting near the pier initially, but you may need to brute force through them. You don't need to lose the wanted level before returning to Donald, so don't worry about a Pay-n-Spray, just sprint for his tower.