First you have to create an account to Robotzindisguise.com . Then you have to buy some hours to the bot, and im not sure if it adds the right after youve paid, but in 24hours you should got the hours on your bot. Then you just download the bot from My Robot page, and when its downloaded, run it, type your RID username and password. You should see how many hours you have left.
I have to say that it is good, even when i have got 0.5black marks. So if your going to bot, RID's MTA bot is the best option. I havent tried V4 now, but probably trying it out in few months.