Click a checkbox, and start a background timer to "uncheck" the next two row checkbox automatically afterwards

When I click a checkbox, then run a background timer, after that will auto click the next two row checkbox. Please help, I can't fix this long time already...

I refer to this example: https://support.google.com/docs/thread/3199678?hl=en

Here is my Google sheet, I was set it to edit mode, u can edit the code in "Script editor": https://docs.google.com/spreadsheets/d/1pSzk8yl1HNoi_njPnYLQxwK34KY_JWJST5Yz8k_CRIU/edit?usp=sharing

Sorry bad English and poor on coding... Please help me

Thanks!