how to use 99 tacoma factory alarm

Hi-
I have a 99 toyota tacoma with the 2 button remote. Right now the top button unlocks and locks the truck. I was told the bottom button can be programed for another toyota. I was also told it could also be used to change the chirp. Does anyone know how to do this? Sometimes after messing with the remote the doors will lock on there own. How do you set the alarm to do this or not do this? What else will this alarm do and how do I program it do do those things? Does anyone have a manual for this alarm?