Do I stain all four side?

Best to install deck first, let weather for 4-12 months, clean and brighten wood, then stain with TWP to just the exposed areas. Not need to do all sides or even 3 sides. You want the wood to be able to "breathe".

TWP does not want you to stain new wood for 4-12 months after install. Staining now could result in the stain failing faster then normal.

I am not familiar with weathering wood. What does it do to the wood and why is it good to do before staining? I tried to research why and i am not really getting the right answers

Weathering allows the stain to be able to penetrate better. If you stain it now, it will fail.

I did a test stain and it turned out to be more orange than red for the redwood on the doug fir. Is there anything I can add to make it more red?

You cannot add pigment to TWP but you can mix different colors of TWP together. What color did you buy and what color do you want it to be when done?

i got the redwood. I would like it to be darker. almost brick red.

The redwood is a very red color in the can. Must be the wood that is causing this. I do not know if you can make it redder but maybe adding some dark oak might make it a darker red. I would get some samples and mix them together to see if that works.

Hi, I would like to know what is the best stain to use in my local. I am in Central New Jersey (summers are hot and humid, winters are regular) staining pine deck and fence.

I would look at TWP or Armstrong Clark stain.