What you will need
Garden sprayer ($10 is good)
Roller or airless sprayer
Pivoting shield (if you use a paint sprayer)
Hand paint container
Oil base stain and sealant
How to do this project
This was the previous state.
We used this deck cleaner. Applied with a simple garden sprayer that you can get for $10. We didn't had the sprayer and applied the first time with a mop. It was such a mess that we had to run to the store to purchase the garden sprayer. Much easier
When using an electric sprayer, it's fundamental to get also the pivoting shield. This will make the job much easier, since you won't have to tape almost anything for an outside job.
I used a sprayer with Olympic elite paint, mountain cedar color. Got it from Lowe's. You can just use a roller or paint brush. Use the paintbrush for small fixes.
Good luck! And send me photos of what you done with your deck!