first, you need to break the project down into small tasks. then create a test project to just do 1 task at a time. do not try to solve the whole project at 1 time or it may become a bit overwhelming.
so you have at least 3 tasks you will need to do within an auto responder:
read incoming text
determine correct response (if any)
send response to room
now each of these 3 main tasks i have outlined may be broken up into even smaller tasks. in programming, there are often many ways to do the same thing, and so it is up to you as the programmer to decide how you want to get the tasks done. instead of just asking for someone else to spoon feed you, you need to learn how to program and create your own code.