I hope the following will be of help.
"Into" is used when soemthing moves from outside to inside. Example: The information goes into the computer. I fell into a ditch.
If you are "onto" something, you are in the process of discovering it which is more imprtant and exciting than you thought. Eample: I guess we are onto something big.
Onto is also used to indicate the place towards which someone or something is directed. Eample: The door opened onto a dark staircase