With the brake handle held firmly closed, loosen the bleeder screw. The
pressure at the handle will drop, and fluid will flow into the tube, along with air bubbles no doubt. Don't be alarmed- just keep the pressure on the
handle and continue to force fluid into the tube. Stop the handle before it reaches the handlebar by closing the bleeder. The best way to do it is to hold firm pressure on the handle, but only loosen the bleeder a bit, so you have
more control over it.
BEFORE letting go of the lever, close the bleeder completely. I can't stress
enough how important it is to never release the handle even the slightest
amount while the bleeder screw is loose, because air will get in. So,
while holding the lever, tighten the bleeder screw as shown. Then, you
can repeat this process several times.