Useful Tips for Noobs
If you want to go loud, ignore the jewelry displays and the cash in the manager’s office. Only focus on the vault. The level of police response will steadily increase as the heist goes on, with each wave of cops having a few more than the last.
The first powerbox is highly exposed, and an easy place to get killed if you wait to do it after ransacking the storefront and manager’s office.
With the latest update, you should have a suppressor and lockpick. So doing it quietly at level 1 is also an option (lucky bastard). I recomend looking up a tutorial on how to use the lockpick.
It’s best to deliberately move it side-to-side, which I wouldn’t describe as a “jiggle”, which the game tells you to do. As for finding everything you need (vault and utility keycards), I would spend a few runs going hot just to open every door and see where everything is, followed by restarting.
After that, it’s going to take a few tries to figure out how to maintain stealth all the way to getting the vault open, but it’s very doable.
Also, if you want to get the jewelry from the storefront, you’re going to have to go hot. So use the stealth portion of the heist to haul the entire contents of the vault and manager’s office into your truck. Then empty the duffel bags and bring each of them into the jewelry store.
Once you’re in the storefront and the shooting has started, work on getting every valuable item into a bag. I recomend falling back up the stairs when the waves of police show up. But once the wave is complete, you’ll have about 30 seconds to keep filling the bags before more show up.
You should be able to get everything in the storefront before it gets too hot to handle. Then just haul the bags to the truck and leave.