They told me that because of the pandemic a reservation is needed to enter, is it true?

Yes it is true

Yep

Yes, there are two slots available. Morning and afternoon.

Yes, you need one. They started out with specific time slots, but now it's either arrive before 1pm or after 1pm I believe.

Ok Thank you

Yes. You pick a time, day, and how many people in your group.

Yes it is true, in fact you can make a reservation a week in advance. Weekends especially are sold out now with the nicer weather.

You can make your reservation up to 7 days in advance