You get the choice between two different approaches to the Jewel Store, one being the Loud Approach and one being Smart. These will result in completely different missions and both have different setups.
Go outside and get in your vehicle, waiting for Franklin to get inside before leaving for the jewelry store. Park at the yellow marker, in front of the construction area, and you will automatically switch to Franklin. You need to get on top of the roof, to the same spot where you took a picture with Michael.
Once you get there, arm yourself with the gas grenades and throw one into the ventilation system. Aim as low as possible on the yellow marker to get it in. When you see the gas coming out, you know you got it right. You will now switch back to Michael, who goes into the store, with everyone passed out. Depending on who you hired as the hacker (hopefully the one with the 15% cut), you only have a certain amount of time to steal the jewelry from the display cases.
Go up to each one and press the designated button to smash and grab. If you got the most expensive hacker, you should have more than enough time to clean the place out. Once you're done or run out of time, head outside and you'll get on your bikes. You now have a 4-star wanted level, so just start driving and following the others.
When you jump off the bridge, make sure you steer to the right and enter the sewers area. Keep going through all of the tunnels until you eventually return to the surface, where you will switch to an armored truck. Continue following your crew and bump into the police vehicles to incapacitate them.
When you reach the end, stop at the marker to load the bikes into the truck, then drive to the Lester's lockup to finish the mission. You will see a break down on how you did on the heist, including everyone's cuts.
|Completing this mission will earn you the Diamond Hard achievement/trophy.|