Also, after burgers are when you ate a burger, but you decide: “eh, why not another?”
After eating an after burger, side effects may include:
Burger overload
Too much hamburgerrrr
Burgeritis
Hamburgerphobia
Hamberg disease
Hamhamham disease
Swelling in the hamburger
Hamburger intoxication
And... Stomach pain.

Ah yes, after burgers.
.
But seriously, to make an after burner I think try to disassemble other peoples builds with afterburners. Then you can see how they mod it with overload and stuff.
An afterburner is basicly a secondary engine. Here’s a copy and paste from Wikipedia:
An afterburner (or reheat U.K.) is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat. Afterburning injects additional fuel into a combustor in the jet pipe behind (i.e., "after") the turbine, "reheating" the exhaust gas. Afterburning significantly increases thrust as an alternative to using a bigger engine with its attendant weight penalty, but at the cost of very high fuel consumption (decreased fuel efficiency) which limits its use to short periods. This aircraft application of reheat contrasts with the meaning and implementation of reheat applicable to gas turbines driving electrical generators and which reduces fuel consumption.[1]

Jet engines are referred to as operating wet when afterburning is being used and dry when not.[2] An engine producing maximum thrust wet is at maximum power, while an engine producing maximum thrust dry is at military power.[3]