There are certain preparatory tasks you must complete before you can continue with the Planning Work for The Podium Robbery in GTA Online's The Chop Shop DLC. The tasks include securing gas masks, rappel equipment, sabotaging the casino, and optionally acquiring masks.

You can always see your tasks laid out on the planning screen. However, you can not start your tasks from the planning screen, you must go to the task locations to begin them.

Instead, you can find these in the free roam.

The tasks are indicated by a green duffle bag on your map. You can complete these tasks in any order. When you go to the task location, you will see a green highlighted circle on the ground.

Walk up to the green marker, and you will get an option to interact with it to start the task.

For The Podium Robbery, you have three mandatory and one optional task.

Task 1: Gas Masks

In this mission, you must steal the gas masks from a fire station.

The fire station garage.

The gas mask crate can be anywhere inside the fire station, but it is always on the garage floor around the perimeter.

Gas masks.

The firefighters will try to fight you.

Once you've acquired the gas masks, you must lose the cops and deliver the gas masks to your Salvage Yard to complete the mission.

Delivering the gas masks to our Salvage Yard.

Task 2: Rappel Equipment

In this task, you must break into a hideout to steal the rappel equipment.

Hideout entrance.

When you reach the hideout, you must eliminate the enemies and look for a blue duffle bag.

You will find multiple enemies inside the hideout.
Rapple equipment.

Grab the duffle bag and leave the hideout.

Once you're out, the enemies will still chase you, but ignore them and deliver the equipment to your Salvage Yard to complete this task.

Task 3: Sabotage Casino

This task is not indicated on the map by a green duffle bag, so some players tend to overlook it or don't know how to start it.

You will notice a small green Salvage Yard icon by the casino icon on your map.

For this task, you must go inside the casino and go to the restroom.
Casino entrance with a green marker indication of a robbery task.

Once you enter the casino, go past the vehicle podium and the lucky wheel. Go into the 'Table Games' section and go around the left side.

'Table Games' section.

Keep moving forward and turn left towards more table games.

More table games ahead.
Eventually, you will come across the restrooms.

Go inside the restrooms and plant an explosive on the last toilet seat.

Planting the explosives.
The task is completed once you've planted the explosives.

Task 4: Masks (Optional)

This task is completely optional and does not affect your robbery at all. Instead, it's related to aesthetics and what mask you wear during the robbery. So, you can completely skip this one if you want.

However, if you still want to do it, head over to the mask shop at the Vespucci Beach.

Mask shop location.

Purchase any one of the mask sets to use during your robbery.

Once you purchase a mask set, your task will be registered as completed.

With these initial tasks completed, you are now ready to proceed to the more involved Planning Work missions.