Creating an Event with an unknown date is a useful way to advertise the potential to run an Event and gauge interest before committing to a specific date and time.
Users will be able to show their interest by registering onto it and when you have enough interest you can decide when best to run it.
If you decide to go ahead with it, you can create a separate Event for the confirmed date and time, keeping unknown Event as a holding area for future events (or overfill for this Event) or you can edit the current Event details with the confirmed date and time.
Create the Event
Begin by creating the Event as you normally would however follow the below guidelines as you work through the Event creation wizard:
Step 1
You can complete the boxes as normal.
Click on Next to move to the next step.
Step 2
Rather than choosing a start and end date, tick the Date and time to be confirmed boxes.
The date and time fields will become greyed out. 
You do not have to enter any details into the CPD or Location sections although you can if you wish.
Click on Next to move to the next step.
Step 3
You can set the date and time up as to be confirmed by ticking the boxes for the registration:
Alternatively, you can add dates by which Users need to have registered and/or cancelled their interest. For example, if you have a provisional date and training provider in mind, it's likely that there is a deadline for you to confirm the date with them. You could therefore set this date up as the final date for people to register onto the Event.
Refer to the create an Event guide if you need help completing the rest of the boxes.
Step 4
Check the details and click on Finish if you are happy or on Previous to return to the steps of the wizard.
Your Event will now be added to your Event List view only (listed in alphabetical order) within the Events homepage.
You will now need to publish it so that Users can find it and register their interest (see publish an Event in a Catalogue for further information).
Change the unknown Event date and time into a confirmed Event
When you have enough interest for your Event and would like to run it, you will need to change the TBC date and time.
Locate the event via the Event List in the Events area (see view an individual Event if you're unsure how to do this).
Click on the name of the Event.
You will be taken to the Event's administration area:
Click on the Time and Location tab.
Remove the ticks from the Date and time to be confirmed boxes.
Set the date as you normally would when creating an Event.
Click on each tab in turn and check that the details are correct, in particular the Registration Details as you might also need to change the date and time in here.