I had the same question and it appears you can do it with the pro version only, I just found the following paste under the Pro Version "manual booking" feature. I don't work for Events Manager, so there may be another way. I'm watching your post also. Good luck!
Adding Manual Bookings
Bookings can also be added manually. You can add a booking any event bookings managment page.
There should be an “Add Booking” button next to the page title:
Adding a booking is much like the user logging in and making the booking themselves. The two differences are that you must select the user to apply this booking to (and if a user doesn’t exist, you must create one beforehand using the wordpress Users > Add New tool) and also decide whether this user has fully paid this event.
If a user has fully paid an event, then a corresponding offline transaction record will also be created and the booking will be marked as paid and confirmed, along with sending a user a confirmation email, opposed to a pending mail if the booking is not paid, and it will be marked as awaiting payment.