Head to the marked location and take a ride with Donovan. He’ll drive you to Marcano’s mansion in Frisco Fields disguised as a helper. You won’t be able to bring any weapons, adrenaline shots, or explosives as well. Once inside, wait for the manager to finish talking to a cook then follow him inside.
Once he tells you to get the guests their drinks, interact with all three bottles to dose them with military-grade LSD. Pick one bottle up then walk to the door. Serve the manager then head outside. Walk around the wake and serve all those visitors with the bottle icon. After Olivia’s speech, you have to serve her bodyguards next. They’ll be marked in the map and they’re also wearing white suits so you won’t have problems finding them. Once done, head back to the kitchen and take a smoke in the smoking area.