The job is quite easy. There are two ways to do this. You can either enlist a willing helper to press the brake pedal as required, or use a pressure bleeding system as I do. I use and recommend this one Sealey
You can pick it up for around £16. The selection of caps it comes with are useless for Alfa, so you need to buy a cap from an Alfa dealer.
Firstly, partially empty the brake fluid reservoir and add clean fluid. Fill the pressure bleeder if using one.
The wheels need to be removed. Start at the rear right as this is the furthest from the reservoir. Clean round the brake nipple, remove the rubber cap & spray with some plus gas or similar.
Now connect up the pressure bleeder as instructed, or get your willing helper ready.
Fit a 11mm ring spanner over the nipple & connect clear tubing & place open end in a container. If using a pressure bleeder, just crack open the nipple and let the fluid flow. Keep a careful eye on the levels in the resevoir & in the pressure bleeder.
If using an assistant instead of the bleeder, get them to press hard on the pedal, open the nipple until fluid flows, then close & then release pressure on the brake. I hate the method as so much can go wrong!
Repeat this on each wheel. The order I followed was OSR - NSR- OSF -NSF
Remember, if like me you have Brembos, the fronts have 2 nipples.
In total I bled around 1L of fluid so It's well and truly flushed.
AFAIK dealers don't bleed at service as it takes too long, they just suck out the reservoir & replace.