Google CERN & all information is there. You can book a visit 15 or 3 days before you want to go but you have to do this at 8.30 am Geneva time & places seem to fill within 2 mins. However there are 2 exhibitions that don't need a ticket open to all & worth seeing even if you don't get on a tour. Good luck
My husband found it on their website.
There are different types of 'visits' available at CERN.
1. The Globe (Universe of Particles) Is free to visit and is open:
Monday to Saturday - 10:00 to 17:00
(with the occasional exception)
2. Microcosm exhibition (just opposite to the globe, through CERN reception), is free to visit.
3. Guided tours of CERN and its experiments, are also free but must be booked in advanced.
Searching the web for "Visit CERN" should show the links for the visit types above.
I hope this is helpful!
You need to book the tours on line. They are all free!! Including cost of public transport there if a tourist.
Get quick answers from CERN staff and past visitors.