can someone explain to me in laymens terms how fuel gets from the fuel tank to the injectors on a stock 2002 duramax ?

is the injector pump the same as a fuel pump ?

The Duramax fuel system consists of one two-stage injection pump, the CP3. It draws fuel by vacuum from the fuel tank through the fuel filter. The first stage gear type pump creates the vacuum draw and feeds the three high pressure plungers that pressurize the common injection rails.