Okay the hose in the picture above goes from the engine intake to the brake booster.
The brake booster is the large round canister on the right, I hope you can guess where the engine is.
You do not want to POUR Sea foam into your brake booster!
IN fact you dont want to pour it into anything.
The vacuum from the engine will actually suck up the sea foam. However you dont want it to suck it up too fast or the engine will die!
You want to keep the engine running and slowly let it suck up the sea foam.....so it will start to bog down, pull the hose out of the sea foam, it will return to a smooth idle, let it suck up some more...etc etc etc...
Let it go through about 3/4 of the can of sea foam, put the remainder in the gas tank.
Then, hook the HOSE BACK UP and make sure it is on there right....take the truck for a drive and WATCH the grey smoke pour out the back....dont worry it will stop.