Welcome to the club.
First question cleaning plates. Use accelerant free gloves, N-Dex brand, the regular nitrile gloves have sulfur in them. I simply polish and wipe with acetone, that gets rid of the fats used in the manufacture of polishing compounds. Don’t over think it. Remember to wipe edges of plates.
A properly exposed B-dag will show the brightest highlight already starting to show when first put under rubylith. The light coming in the lens has red wavelengths in it that will start the print out process. For an experiment do a several hour exposure, you sill see lots of this effect and it makes neat images. My best development ever was placing rubylith covered plate holder in a north facing window in my house and going off to work, comeback and it was perfect!
Gilding not required on B-dags, rarely does it improve them, more often ruins, but does make them much tougher. Never pour solution on dry plate it will stain, keep plate in low pyrex with just a little water over the surface. I make my gold solution a bit stronger to compensate for the water and pour not on plate but next to and allow to mix with the water. Heat just speeds up reaction, you can do a “cold Gilding” by leaving it alone and watching, Ive done it over several days or a few hours, flood with water when it looks good. If you are in a hurry you can put in the microwave, as long as metal is fully submerged it will not spark! Watch carefully for steam, pull out immediately then let sit till you are happy. If bubbles form on the surface it will usually not result in a good image.