How do I use boards from a privacy fence to make flooring?

I would consider using nails like you would put down hardwood floors. If not, Power Grab is a good adhesive that we have used to hold blocks in place.

The first thing I would check once you remove the privacy fence is to see if the boards are warped and make sure that you would have enough wood to complete your project. If they are rough I would consider running the boards through a wood planer to make them smooth and a consistent thickness or you can spend some time sanding. Here's a quick little video to shoe you how one person did it using cedar fence boards: https://www.youtube.com/watch?v=tzLSykm-sEI

I researched this and think Kathy may be correct. There are instructions to use the planks on walls but nothing re flooring. Here is some info on the wall, basic install for floors. Pallets are a better option, cut plywood, mdf, etc.

This was answered as being "long and arduous"

https://www.houzz.com/discussions/4577899/can-i-use-my-old-cedar-fence-wood-repurpose-as-flooring-any-suggestion

https://homeguides.sfgate.com/finish-reclaimed-wood-fencing-46965.html

https://www.youtube.com/watch?v=nS-MH03CDOE

https://www.diypassion.com/2016/05/23/the-best-way-to-up-cycle-an-old-fence/

https://www.profloortips.com/hardwood/pallet-wood-flooring-guide/

https://homeguides.sfgate.com/use-wood-pallets-create-floor-34723.html

https://www.creeklinehouse.com/how-to-install-beautiful-wood-floors/

I'd nail them down.

Here's how we did our floors using just basic pine, you could use the same principle with fence boards: https://www.hometalk.com/diy/floors-ceilings/inexpensive-wood-floor-that-looks-expensive-four-years-later-43273708