As stated above, you'll get an auth code emailed to you. The email will be titled "RuneScape Bot" it will contain a code in bold starting with 343x usually for perfect fighter.
To use the auth code you have to download the client. I suggest going to
http://www.rsbots.net/download it's the shorter of the URL's that all take you to the same place.
Once you have the client downloaded, extract it into a folder on your desktop named BotClient. Then click the install-windows batch file to install it.
Once installed you'll see a few batch files that you can use to run it. I suggest Run.bat (the regular one) or run-with-cmd-lowram batch if you have 1GB or less RAM.
Opon running, a data protection screen will appear, create a question if you'd like, you don't have to. Note: The answer is case sensitive.
After the data protection screen you'll encounter the auth and news screen. Input your auth into the textbox there and click the Add Auth button.
After adding, it should show Perfect Fighter - Gets you 138 combat. as well as Bot Limit 1 and Runnable.
Click continue, the client will load, the bot will start. And you'll be good to go
