Smoother Movement with Vector3.Lerp

I have a simple movement script for my Player to move a certain Distance to the left/right on a Platform with 3 Lanes. Right now the Player just ‘teleports’ to the Lanes. I want to make the movement look smoother with Vector3.Lerp, but i just fail at every atempt i try to implement it into my Code. I would appreciate an example on how to do it cause i have been stuck at this point for a bit now.

        if (Input.GetKeyDown("a"))

            // Do i need to calculate it with a speed var.?
            // Because if i do, the Movement becomes 'uneven' meaning sometimes the
            // Character will move too far, instead of a SET distance everytime

            transform.Translate(new Vector3(-6, 0));

public float moveSpeed = 2;
if (Input.GetKey(KeyCode.W)){
transform.Translate(new Vector3(0,0,1)moveSpeedTime.deltaTime);