Hey Chunfung,
Thanks for going Pro and welcome to the forums! No need to be sorry, with your license comes 1 year of pro customer support and we are more than happy to help you with your questions and issues to the best of our knowledge. 🙂
Let’s tackle your questions one-by-one.
1. is it all visitor can add the events or need login
There is a setting for this under Events > Settings > Community > Allow anonymous submissions, check the screenshot here:

If the box in unchecked, then anybody can submit events.
If the box is checked, then only users who register can submit events.
2. add events will show on the Calendar or only show on the list?
If the events are published, then they will show up in all calendars, not only on the list.
3. can they add event , Status be Pending Review.
Yes, there is a setting for this too, just a bit below the previous setting. Events > Settings > Community > Default status for submitted events
I hope this helps! Let me know if you have any more questions.
Cheers,
Andras