To create an event you have to use the timeline area on the left of the ExWeb interface.
By default this is set so that you can create an event every five minutes.
To change the interval period, right-click on the time line to the left and select the period you wish.
Once you have done this you are ready to create an event.
There are a couple of ways to do this.
To start, you can simply double left-click anywhere on the time-line.
You can change the start and finish time manually afterwards, so it doesn't make a difference where you click.
Alternatively you can right-click on the time-line and then click on the New Event option in the menu that appears: