open the qt wallet and let it sync

download minerd (cpuminer) for linux, I'm using cpuminer-2.5.0, any version of cpuminer will do if it supports the scrypt algorithm

go into your home directory and find the .marblecoin directory and go into that

edit or make a file called marblecoin.cong with the following lines

rpcuser=x
rpcpassword=x
rpcallowip=127.0.0.1
rpcport=32428
port=32427
staking=1
daemon=1
listen=1
server=1
gen=1
addnode=node.walletbuilders.com
addnode=104.31.86.52
addnode=216.146.43.70
addnode=74.208.43.192


save that conf file, close thee marble-qt wallet and open it up again

go in the directory where minerd is and run this line from a terminal

./minerd -a scrypt -o http://127.0.0.1:32428/ -u me -p x