Translate Craig Reynolds's steering behaviors

I've been reading some literature on Craig Reynolds' steering behavior algorithms, and trying to translate them to unity. I'm pretty new to Unity, so I'm not sure if I'm using the correct functions when replacing his code.

This is the simple algorithm I am trying to implement:

 // A method that calculates a steering vector towards a target
 PVector steer(PVector target) {
    PVector steer;  // The steering vector
    PVector desired = PVector.sub(target,loc);  // A vector pointing from the location
    to the target
    float d = desired.mag(); // Distance from the target is the magnitude of the
    vector
 // If the distance is greater than 0, calc steering (otherwise return zero vector)
 if (d > 0) {
    // Normalize desired and give it magnitude determined by maxspeed
    desired.normalize();
    desired.mult(maxspeed);
    // Steering = Desired minus Velocity
    steer = PVector.sub(desired,vel);
    steer.limit(maxforce);  // Limit to maximum steering force
 } else {
      steer = new PVector(0,0);
   }
  return steer;}

So far, this is what I have. I am stuck on the last Lerp that should take the velocity, but I'm not sure what my second vector would be, since Lerp takes (vector3,vector3, float) as arguments.

 enter code here

 function steer(target : Vector3)
 {
 var maxSpeed : float = 5;
 var maxForce : float = 5;
 var vol : float = 2;
 var steer : Vector3;  // The steering vector
 var loc = transform.TransformPoint(Vector3.zero);
 var desired : Vector3 = Vector3.Lerp(target,loc,  Time.deltaTime);  // A vector pointing from the location to the target
 
 var d : float = desired.magnitude; // Distance from the target is the magnitude of the vector
 // If the distance is greater than 0, calc steering (otherwise return zero vector)
 if (d > 0)
 {
     // Normalize desired and give it magnitude determined by maxspeed
     desired.Normalize();
     desired * maxSpeed;
     // Steering = Desired minus Velocity
     steer = Vector3.Lerp(desired, vol,  Time.deltaTime);

     steer = Vector3.ClampMagnitude(steer, maxForce); // Limit to maximum
          steering force
    } else    {steer = Vector3(0,0,0);}
       return steer;
          }
 

Thanks in advance for any input!

EDIT: Also, I am aware of Unity Steer, but I'd like to implement this myself so I grasp the concepts.