Pick up, drop, rotate, and zoom a rigidbody gameObject

Sorry to hear you're frustrated. That's a fact of life in game development! Shrug it off, learn from your mistakes and move on!

I don't want to write the entire script for you, but I can describe the steps and give you some code that will hopefully point you in the right direction :)

Please note I usually use C# so my JS might not be 100% on-point. Anybody, please correct any mistakes (community edit is on). I also didn't test all of this, so it might not be totally correct.

In your script's Update() function:

1. If the mouse is down and you don't have anything selected, perform a ray cast from where the camera is to where the mouse click is and if there's a hit, save it to some var you have in your script's global scope (can be seen/accessed outside of your Update() function), let's call it grabbed (so somewhere outside of Update() you would have something like var grabbed : GameObject).

     if(Input.GetMouseButton(0) && !grabbed){
            // grab any raycast hit
            var hit : RaycastHit;
            var ray : Ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (Physics.Raycast(ray, hit)){
                // You might want to do some sort of filtering here so you don't grab things you don't want to, such as the ground (a different topic altogether)
                grabbed = hit.collider.gameObject;
            } else {
                grabbed = null;
            }
        } else {
            // set grabbed to null so we know we're not holding onto anything
            grabbed = null;
        }
   
   

2. Now that you know which object you're grabbing, you can manipulate its transform as you please, still in the Update() function after step 1

     if(grabbed){
             // my guess is that you're also going to want to stop the object from moving/rotating on its own while it's grabbed
             grabbed.rigidbody.velocity = Vector3.zero;
             grabbed.rigidbody.angularVelocity = Vector3.zero;
        
        
            /* rotate by 90 degrees */
            if(Input.GetKeyDown(KeyCode.R)){
                var euler = grabbed.transform.rotation.eulerAngles;
                euler.y += 90.0f;
                grabbed.transform.rotation = Quaternion.Euler(euler);
            }
        
        
             /* move by mouse movement */
             // NOTE: These have to be defined in Edit -> Project Settings -> Input as an axes, should be there by default.
             float scroll = Input.GetAxis("Mouse ScrollWheel");
             float mouseDX = Input.GetAxis("Mouse X");
             float mouseDY = Input.GetAxis("Mouse Y");
            
             // NOTE: This will probably move the object by WAY too much.
             // You will need to make these numbers smaller
             // like, say, divide them by 2 or something; test to figure out what works best for your scenario
             // If it moves on the wrong axes, try mixing these around or negating them.
             var trans = Vector3(mouseDX, scroll, mouseDY);
   
             // Rotate translation to correlate to camera
             // Not sure if these next two lines work in JS, let me know
             trans = Camera.main.transform.rotation * trans;
             grabbed.transform.position += trans;
         }