how to make automatic gradual acceleration

Hi,
i need help, my programing looks ctrl+c and ctrl+v :smiley: but when i read codes i understand relatively…
this is my problem, i need give automatic gradual acceleration to code, which is below…

using UnityEngine;
using System.Collections;

public class Mover : MonoBehaviour
{
public float speed;
private Rigidbody rb;

void Start()
    
 {
    rb = GetComponent<Rigidbody>();

    

    rb.velocity = new Vector3(0.0f, speed, 0.0f);
        
}

void FixedUpdate()
{
    
}

}

When people usually think of ‘speed’, they are actually referring to their max velocity. So instead of setting velocity to speed all at once, you’ll need to slowly add to velocity. This is called acceleration.

float speed = 5f; // max velocity
float acceleration = 0.1f; // how fast to increase velocity
float velocity = 0f;

void Start()

{
	rb = GetComponent<Rigidbody>();
}

void FixedUpdate()
{
	// add to velocity
	velocity += acceleration;

	// check if we are at our top speed
	if (velocity > speed) {
		velocity = speed;
	}

	// then set it to rb
	rb.velocity = new Vector3(0f, velocity, 0f);
}