Unity3D How to move ball left & right only?

Hello,

Please be informed that my code is already created and I want it so that after I move the ball left or right, it doesn't just shoot straight forward. I want it so that I can either lift my finger, then touch it again OR move it upwards (as in forward) and shoot the ball forward. Please see the screenshot and the code so you know what I mean. Please do not just throw some touch finger code as I might not understand how it can be fitted into my existing code. I'm also not an expert and might not understand how this can be done. Any explanation anyone can give to me to know how it works would be really kind and nice. I look forward to extra effort made.

 

Dont use addfoce, just change the velocity. Then you can keep the forward speed constant and lerp to your finger on the other axis

 

@JeffDUnity3D,
Where do I find lerp code? Can you help? I'm unsure what I'm doing.

 

Google! Perhaps try a search like "unity lerp documentation" followed by "unity lerp tutorial".