what is best way to apply stain?

We like spraying with back brushing with an exterior stain pad applicator.

What is back brushing?

If you spray you may get drips and runs. Back brushing the wet stain will ensure the stain is applied evenly and correctly.

I am totally new at this. Still not sure what "back brushing" is. Is it going over the whole deck with the exterior stain pad applicator you mentioned above, or just the drips? And, is that applicator a long handle applicator? Alxo, do you do a deck in sections? I don't understand how you could spray the whole deck then walk over it with an stain pad? I also have a question about how to prep our deck. Probably in wrong place but I'll give it a shot. We built a new house with new cedar porch. Had to wait about 1 1/2 yrs before staining. Unfortunately, we had no idea what we were doing and did it on probably the hottest day of summer. It dried so quickly that each patch showed the overlap and looked terrible. By the next year, it was totally peeling. Do we have to resand the whole deck, or only the peeling parts, or as I was reading, use the stripping and brightener before staining again? What is the best time to stain, and again, do we do it in patches and how do we avoid the overlapping marks? Oh, and what type of sprayer can you use? We just have a pump sprayer that we use for Round Up etc. It is also pressure treated Cedar.