An arteriovenous fistula is a surgical anastomosis of an artery with a vein, bypassing the capillary bed, to allow the faster flow rates needed for hemodialysis. similarly, an arteriovenous graft serves the same function but utilizes a synthetic tube, not the patient's naive blood vessels, to bridge arterial and venous flow while avoiding tiny capillaries.

how to explain this to a person with no medical background ?

An arteriovenous fistula is a surgical procedure where the doctor will surgically connect and artery to a vein in your arm which will increase the flow of blood needed for your dialysis treatment.  

An arteriovenous graft is a surgical procedure where the doctor will insert a looped plastic tube in your arm that connects an artery to a vein increasing the flow of blood needed for your dialysis treatment.

Explanation:

well i’m not to well in health but if the body produces more standard fat then the fat will convert most of it into energy and give all the muscles nutrients (sorry if it was wrong