New to linux, need to find and install my wireless driver AC-8260

I suspect your device simply needs firmware. Verify:

sudo modprobe iwlwifi
dmesg | grep iwl

There should be a message that the needed firmware is not found. If so, please download this file to your desktop: https://wireless.wiki.kernel.org/_media/en/users/drivers/iwlwifi-8000-ucode-25.30.13.0.tgz as well as this: https://wireless.wiki.kernel.org/_media/en/users/drivers/iwlwifi-8000-ucode-15.227938.0.tgz Right-click each and select 'Extract Here.' Now, back to the terminal:

cd ~/Desktop/iwlwifi-8000-ucode-25.30.13.0
sudo cp iwlwifi*  /lib/firmware
cd ~/Desktop/iwlwifi-8000-ucode-15.227938.0
sudo cp iwlwifi*  /lib/firmware

Reboot and your wireless should be working. If not, post diagnostics:

sudo modprobe iwlwifi
dmesg | grep iwl

Based on your diagnostics, I suggest that you update the driver iwlwifi. Download this package to your desktop: https://www.kernel.org/pub/linux/kernel/projects/backports/2015/11/15/backports-20151115.tar.gz Right-click it and select 'Extract Here.' Now, back to the terminal:

sudo apt-get install linux-headers-generic build-essential
cd ~/Desktop/backports-20151115
make defconfig-iwlwifi
make
sudo make install

Reboot and tell us if there is any improvement.

You have compiled the driver for your current kernel version only. When Update Manager installs a later linux-image, after the required reboot, you must recompile:

cd ~/Desktop/backports-20151115
make clean
make defconfig-iwlwifi
make
sudo make install

Please retain the file and these instructions for that time.