How do I fix these errors

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class randomspawner : MonoBehaviour { 

public int spawnRadius = 30; // not sure how large this is yet..
public int agentRadius = 5; // agent's personal space
public GameObject agent; // added in Unity GUI

Vector3 originPoint;

void CreateGroup()
{
    GameObject enemy = GetRandomSpawnPoint();
    originPoint = enemy.gameObject.transform.position;

    for (int i = 0; i < groupSize; i++)
    {
        CreateAgent();
    }
}

public void CreateAgent2()
{
    float directionFacing = Random.Range(0f, 360f);

    // need to pick a random position around originPoint but inside spawnRadius
    // must not be too close to another agent inside spawnRadius

    Instantiate(agent, originPoint, Quaternion.Euler(new Vector3(0f, directionFacing, 0f)));

}
public void CreateAgent3()
{
    float directionFacing = Random.Range(0f, 360f);

    // need to pick a random position around originPoint but inside spawnRadius
    // must not be too close to another agent inside spawnRadius
    Vector3 point = (Random.insideUnitSphere * spawnRadius) + originPoint;
    Instantiate(agent, point, Quaternion.Euler(new Vector3(0f, directionFacing, 0f)));
}


}

Assets\random spawner.cs(15,24): error CS0103: The name 'GetRandomSpawnPoint' does not exist in the current context

Assets\random spawner.cs(18,25): error CS0103: The name 'groupSize' does not exist in the current context

Assets\random spawner.cs(20,9): error CS0103: The name 'CreateAgent' does not exist in the current context