I registered and got the booklet.
Thing is, the process is very subjective. Every gallery is different, every show is different, every curator is different. In my rather successful experience it boils down to:
Know that it will cost you money before it makes you money
Know how galleries operate in general
Know the gallery you're approaching specifically; style, staff, philosophy, other artists, geographic area, sales, town/city info, etc.
Have the right work
In the right format
Get it in front of the right person
With the right presentation
At the right time
Be prepared to provide whatever they need; art, fulfillment, informational materials, personal interaction.
If you think you can just cold email a gallery and get in, you're wasting your time. They put effort and money into the art and artists they represent. Show up ready to reciprocate. It's not a passive endeavor.