It could possibly take over 1000+ years to solve a block, but it is fun nonetheless. CPU Mining does make your CPU run hot so you have to be careful and keep it well ventilated or propped up off the table if it's a laptop.
Search on Google for "Solo CPU Mine <Windows/Linux> <Version> Bitcoin Tutorial" and try different tutorials for your operating system.
Basically, you download Bitcoin-QT or Bitcoind and then add the line "server=1" to the bitcoin.conf with a username and password. On Linux it's home/.bitcoin/bitcoin.conf and sometimes you have to create the file. Then you'll need a CPU miner software like minerd (cpuminer) or cgminer and then configure the software to mine CPU and not GPU.
bitcoin.conf:
rpcuser=username
rpcpassword=password
server=1
rcpallowip=127.0.0.1
rcpallowip=localhost
rpcport=8332
With minerd you just type into the Terminal/Command Prompt once Bitcoin-QT is running which acts as a server:
minerd --url
http://localhost:8332 --userpass username:password
If you mine a block then the 25 BTC reward will automatically be sent to your wallet. Sometimes a new address may be generated in your wallet.
You'll get around 2-40 MHash per second if you're lucky and most likely will never solve a block. Once it's setup it's easy to start the miner. You can let it go every now and again and maybe you'll see 25 BTC in your wallet one day. Good luck