Left-hand side of an assignment must be a variable, property or an indexer

Hello, I’m just starting out with unity, and for some practice to get parts of a tutorial in my head, I decided to create my own version of a character controller in C#…
I have figured out how to solve all but one my errors that I get… which is Left-hand side of an assignment must be a variable, property or an indexer. I have tried to solve this problem but then I get some other silly error which I can’t figure out.
here’s my code :

 using UnityEngine;
    using System.Collections;
    
    public class capsule_move : MonoBehaviour {
    
    	//variables
    	public float speed ;
    	public Transform player ;
    	public float deadzone ;
    	//functions
     
    	//move
    	void FixedUpdate () {
    	if (Input.GetAxis("Horizontal") >deadzone) {
    		player.rigidbody.AddForce = new Vector3(speed,0.0f,0.0f)* Time.deltaTime ; 
    							}
    	
    	}
    }

PLZ HELP MEEHH

AddForce is a method, not a variable. So you would call it like:

player.rigidbody.AddForce(new Vector3(speed,0.0f,0.0f)* Time.deltaTime); 

Note that ‘speed’ is a good term for the variable used here since the AddForce() pushes the object and therefore does not directly correlate to a specific speed. That is, don’t expect your object to move the specific speed used. In fact, without drag, the object will continue to accelerate from this code.