How to adjust the speed of an object?

I got this script that makes it so then a game object travels through certain transforms. I didn't make this and I'm not familiar with C#, so I don't know how to make a variable that adjusts the speed. So, can anybody let me know how I can change the speed with a variable? Here is the script:

 public class randomMovement : MonoBehaviour {
     //Here I am defining a new array called "targets", with an array length of 3.
     //This means that there will be 3 transforms in my array.
     //I can assign these in the inspector window.
     public Transform[] targets = new Transform[3];
     //Here I am defining an int variable which i can use to change the current "targets" transform to use.
     public int curTarget = 0;
  
     void Update() {
        //Check if we are within 1 unit of our target (reduces risk of error - object could miss target which is what causes yours to circle the target)
        if((transform.position - targets[curTarget].transform.position).magnitude < 1f) {
          //When we are within one unit of target, switch to the nex target(or the next transform in the array).
          curTarget++;
          //When our current target reaches the length of the array, we will loop it back to 0 so that it repeats.
          if(curTarget > 2) {
           curTarget = 0;
          }
        }
        //Move forwards
        transform.Translate(Vector3.forward * 3.0f * Time.deltaTime);
        //Always look at the current target
        transform.LookAt(targets[curTarget].position);
     }
 }