To have the possibility of being FBI or SWAT member, you need to join to
ARPD.
Crates, ok.
First of all you can create stashes with crates by first adding something to your pack (/addpack <item> <amount>), let it be note, cash, weapons, drugs.. Pretty much anything you can pick up, except phone

Then, when the items are in your pack, oyu just type /stash and it'll spawn a crate directly below your feet.
Then there's the mini-mission crates.
Sometimes the script announces a mini-mission with teal text, saying there's a crate and it's location. You must race everyone else to that crate and have atleast 1 other player with you to /pickcrate and then the script informs you where to go to sell the goods from the crate. Drive to the location script told you and you will find a blue sphere, just walk in it and you sold the goods

Bankrobbery...
For admin to enable a bankrob, you need a group of players ready to go with one of you carrying
5 explosives. Then the admin will check if the balance of cops and criminals is good enough, if it is, the bankrob will be enabled. However, if the balance is bad (8vs1) the admin in question will not enable bankrobbery and instead will tell you that the balance is not good enough. Also bank robs can't happen every other hour, since that should be rather rare occurence.