carrot/assets/Script/MainScene.ts

import { _decorator, Component, director, instantiate, Node, Prefab, resources } from 'cc';
import { CountDown } from './CountDown';
const { ccclass, property } = _decorator;

@ccclass('MainScene')
export class MainScene extends Component {
    @property(Prefab)
    countDown:Prefab;
    start() {
        
        let countDown = instantiate(this.countDown);
        console.log(countDown.active)
        
        director.getScene().addChild(countDown);
        countDown.setPosition(100,110);
    }


    update(deltaTime: number) {
        
    }
}