The pros that drywalled most of my house before used the paper faced drywall corners so I got some for a small fireplace job that I am working on. I realize theres alot of dispute about which is the proper corners to use but really looking for application advice for the paper faced ones.
from instructions its not clear on steps and number of coats. It appears like
1. first step is to apply mud to wall, stick corner on and then put a thin layer mud on outside (not clear if I do the later) , let dry.
2. Apply another wider coat of mud feather it to wall let dry.
3. apply final coat coat of mud let dry, sand if needed.
You need a continuous layer of mud under the paper. You just need enough layers of mud on top of the paper so you don't expose the paper when sanding, and also achieve a smooth surface.
When cleaning anything including baby diapers, it is better to sweep off or scrape off as much solid and semisolid material as you can first. (1) Less cleaning fluid or detergent needs to be used, (2) Less of a mushy mess which in turn means that bleaches or disinfectants will be more effective.
I would not apply a thin coat over the first coat. Let it dry first. Then apply the second coat to only one side of the corner first. This allows a clean edge to work with. If trying to coat both sides of the corner at the same session your knife cuts into the other corner and you continue to chase the problem. Doing one side at a time makes this much easier for beginners.