To have access to your event, first it needs to be live and the person needs to be part of the attendees list or use the event code of the event.
See: Make the event live
You are able to establish the code from the Settings of the event
See : What is the event code?
If you and your colleagues would like to test the platform, you can set the event to live temporarily so that you/they are able to create an account and add the event code.
You can also send them Test emails that will give them access to the platform.
If as an organiser you wish to test out the platform, simply click on the “see event” under the event name on the top left to access your user interface.