Command-line install instructions:
sudo apt-get install apt-transport-https
wget -qO - https://z.cash/gpg-pubkeys/zcash.asc | sudo apt-key add -
sudo echo "deb https://apt.z.cash jessie main" | sudo tee /etc/apt/sources.list.d/zcash.list
sudo apt-get update
sudo apt-get install zcash
zcash-fetch-params
mkdir ~/.zcash
cd ~/.zcash
echo "rpcuser=username" > zcash.conf
echo "rpcpassword=`head -c 32 /dev/urandom | base64`" >> zcash.conf
echo "gen=1" >> zcash.conf
zcashd
Explainer video: https://www.youtube.com/watch?v=5ahQZZYcntQ