It took me about an hour (just over over) to fill 5 liters of fluid. It drained
about 4 1/2 liters, and after getting to temp and draining, about 1/2 liter drained out.
Before filling with fluid, you do put in the inter tube (8mm), and then the
drain plug (14mm). Fill with fluid, measure what drains out, add at least
that much back in. Start the car, shift the trans through the gears, and wait for the fluid to get to temp (40C), using either VCDS or a temp gun to check the temp, then remove the drain plug only (14mm), let the overflow fluid drain, while
the car is running, then replace the drain plug and tighten when the fluid stops.