It's been awhile so this is what I recall doing:
Separate an egg york from the egg white and mix the yolk throughly. We would take a bit onto out fingertips and smear a thin film on about half of a large white bowl at the anticipated water line. Thin is the key so when it drys it sticks good. We'd let this dry.
After the yolk had dried, we's add temp adjusted water and add the fry. A light will be needed over the bowl with a airline bubbling very ,very slowly. The egg yolk should draw the fry to it as it is darker than the bowl. The egg will quickly foul the water so after a brief feeding, you;ll have to remove the fry.
You might consider doing several bowls with egg at once, then refrigerate after drying...just make sure it is not too cold when you add the water.
Another way we tried was soft boiling the egg and using the yolk as above. I'm sure others will weigh in.
The most challenging part is doing this 14 times a day or more and not damaging the fry in the handling. Jack Wattley used a turkey baster and we did too.
Good luck! This is perhaps the most difficult and demanding aspect of breeding these fish in my opinion.