The way to do it with loose balls is as follows (I should make a video of this, but hopefully I can explain well enough):

1. After cleaning everything thoroughly put a good glob of grease on your fingertip and place it in the fixed cup by inserting your finger and then wiping toward the outside of the cup. Repeat all the way around until you have a generous continuous ring of grease.

2. Take a bearing in your left hand and place it in the cup, guiding it into place with your other finger coming through from the adjustable cup side. Repeat until there are 11 ball bearings. Put a good bead of grease in the adjustable cup and place 11 balls in it. Insert the spindle into the adjustable cup (make sure it's the left hand end of the spindle). Rotate the spindle around and remove. There should be a continuous surface of grease on the inside and outside radius - if not add a bit more grease and check again.

3. Place the spindle back on the adjustable cup and grease the cup threads slightly. If there are openings in the bottom bracket to your frame tubes I would recommend a BB sleeve to protect against dirt. Place the sleeve over the spindle and carefully insert into the bottom bracket, guiding it into place with your left finger from the fixed cup side placed on the end of the spindle. Screw the cup in while maintaining pressure so that the bearings stay in place. When you meet resistance from contacting the other side you are ready to adjust.

Last word on loose balls - Grade 25 is tight tolerance (roundness), grade 100 lower, etc.

Have fun, bye!