I'm assuming you have the geth console installed.

In a directory of your choice unzip the following file
Test Server
This will create a directory named testServer

move into the testServer directory and initialise geth with this command

geth --datadir data init genesis.json

then start geth with

geth --datadir data --networkid 20160720 --ipcpath < path to ipc file> console 2>geth.log

replacing < path to ipc file> as follows :

~/Library/Ethereum/geth.ipc for Mac
or ~/.ethereum/geth.ipc for Linux
or ~/AppData/Roaming/Ethereum/geth.ipc for Windows

If you start geth with the ipc flag, then your Ethereum wallet will connect to your geth instance and hence the private network which is useful but not necessary

You should then be connected to the private network and you will see block synchronisation

If you are using the wallet you can use the GUI to create accounts and contracts
in the geth console you can create an account with
then start mining with

If you want to use rpc and unlock your account you can run

geth --datadir data --networkid 20160720 --ipcpath < path to ipc file> --rpc --rpcaddr=localhost --rpcport=8545 --rpccorsdomain "*" --unlock 0 console 2>geth.log