Immigrationboards.com

I was reading guide to fill-in form AN on UKBA website,and it says

"We expect you to arrange to attend a ceremony within 3 months of receiving your invitation"

does it mean when they send the letter of invitation for ceremony, they do not assign a date?
or does it mean they assign an specific date but an individual can chose a later date within 3 months?

You will be sent the contact details of your local authority with whom you need to arrange a date and or private ceremony if you want it that way.