1. Read the tutorials
2. goto 1.
Put simply:
record the sound
save it as a wav and an ogg file
use the wav file to create a lip file (if it is a voice)
save the ogg and lip files in the folders the tutorials will tell you about
modfiy the file description.ext in the way the tutorials will tell you about
use the say command or the playsound command.
read the tutorials and then then ask any specific question about things you are not clear on and you will get some good answers.