Collisions without physics

Hi!

I'm trying to make the simplest platformer prototype with the simplest physics (falling with gravity, moving left and right, and (maybe) jump). For example:

     void Move () {
         if (!isDying || !isDead || !isShooting || !isFalling)
         {
             float amountToMove = Time.deltaTime * Input.GetAxis("Horizontal") * playerSpeed;
             transform.Translate(Vector3.right * amountToMove);
         }
     }
         
     void ApplyGravity() {
         
         float amountToMove = Time.deltaTime * gravity;
         transform.Translate(Vector3.down * amountToMove);
         
     }

The problem is i don't know how to make collisions without physics and with isKinematic enabled. The only thing i know is to use a OnTriggerEnter function, so added a isTrigger to all objects and wrote (Hero.cs):

     void OnTriggerEnter (Collider otherGameObjectCollider) {
         if (otherGameObjectCollider.gameObject.tag == "ground") {
             Debug.Log("ground/wall collision");
         }
     }

I know that i need stop my hero to prevent falling (walking) through the ground but i really can't think it out.

Sorry for the dumb question.