Firstly, add a “non-free” component to /etc/apt/sources.list, for example:
deb https://httpredir.debian.org/debian/ jessie main contrib non-free
Wi-Fi:
https://wiki.debian.org/brcm80211
apt-get update && apt-get install firmware-brcm80211 modprobe -r brcmsmac ; modprobe brcmsmac
VGA:
https://wiki.debian.org/ATIProprietary#jessie
aptitude update apt-cache search linux-headers (search full name for your architecture, like linux-headers-3.0.16-4-all-amd64, install that) aptitude -r install fglrx-driver aticonfig –initial aticonfig –initial=check # to make sure that you have fglrx section in X11 configuration reboot