There is a property destruction meter at the bottom-right corner of your screen. The more property you destroy, the more it fills up. Your objective is to completely fill this bar by destroying the Lost MC property.
Most of the property will have a flammable container by them. Shoot them to cause an explosion and destroy the property.
You can also use your personal explosive equipment such as the RPG, sticky bomb, grenade, etc.
After destroying the property, you must go to Millar's Fishery to loot the drugs. Once you get to the location, eliminate the enemies, and collect the drugs.
The drugs are not hidden, and they will flash right in front of you. There are ten total drug items you must collect. Also, when you're near the drugs, they will be highlighted as green dots on your mini-map.
Here are the locations of all the drugs we found at Millar's Fishery.
Drug 1
On the table outside the small blue house right as you enter Millar's Fishery area.
Drug 2 & 3
Both drugs are on the shelf inside a large warehouse directly in front of the small blue house. As you enter Millar's Fishery, it is a large building to your right.
Drug 4 & 5
These two are inside a small lab that is directly ahead of you as you enter Millar's Fishery. Walk past the large warehouse and small blue house, and you will see another huge building in front of you. It says "Millars Boat Shop" on the building.
This building is a secret lab. However, you cannot enter it head-on. You must go around the back to enter via a backdoor. You will see a blue marker allowing you to enter the building.
Once inside, go downstairs but be careful as there are some Lost MC members inside. One of them wields a shotgun so prepare to shoot.
There are not a lot of enemies inside. You will face only one or two of them downstairs. Eliminate them and collect the flashing-wrapped bags. After that, you can exit the same way you entered the building.
Drug 6 & 7
When you exit via the backdoor, go left, and you will see two more drug items directly ahead of you by a parked van.
Before approaching the drugs, be wary of your left side, as more Lost MC members might be coming from that side.
One of them will be on a rolling table, and the other will be on a shelf. Collect them both and continue moving forward (not towards the Docks).
Drug 8
Keep moving forward until you reach a small turn that takes you out of Millar's Fishery.
However, instead of continuing the path, turn right, and you will find a red lifeboat. The drug is inside this boat.
Drug 9 & 10
Now backtrack all the way to where you came from up until the point where you collected drugs 6 & 7. From here, make your way towards the Docks.
Go down a descending platform, and you will find two more drug items on a wooden crate to your right. Collect them, and you're done.
Once collected, you don't have to return to Millar's Fishery. Instead, you will find a Dodo plane at the Docks.
Get into the plane and fly it to The Freakshop to complete the mission.
After causing significant damage to the Lost MC, you're ready for a more psychedelic experience in the next mission: Uncontrolled Substance.