How does a fistula work?

My mother is a kidney disease patient and the doctor has advised to get a fistula done for her. How does this work?

You see a surgeon. He places a fistula in arm. It takes a few months to become fully functioning, so get it done ASAP.

Fistula is the best modality for dialysis

Creates high blood flow just under the skin

Fistula is created by vascular surgeon, which is a connection between artery and vein. This is needed for dialysis.