Option 1) Use the search function which is easily accessible in the upper right hand corner of the page.
Option 2) Look through the first few pages of Ask a Pro and the Tutorials forums. Most rudimentary things which you might need an answer to have already been posted there.
Option 3) Look on the ComputerCraft wiki. It provides all the information which you need to succeed in ComputerCraft.
Option 4) Google it. Of course if it is ComputerCraft related then you may not find an answer, but it is always worth giving it a shot.
If you have done all four of these things and you are still confused, you should ask on the forums for help. Please keep in mind that you need to post your FULL CODE for us to be of any help to you - people are not going to spoonfeed it to you or write the entire code for you. Another thing to note is that if you want people to help you, they are much more likely to do so if you put your code in a readable format such as within code tags or on pastebin.
The purpose of this post is not to bash noobies to ComputerCraft or lua, but it is my opinion that the 'instant gratification' which many new users seem to require is becoming more than annoying to those who would otherwise be happy to provide help.
Regards,
-Challenge.Accepted
Note: I do not mean to behave as if I am a moderator or an incredibly important user, I merely feel as though this emphatically needed to be stated by somebody.