One of the major logistical challenges you have to deal with when organizing a seminar is that of getting a venue for the seminar. In this respect, the main challenge is that of figuring out whether the venue you desire will actually be available on the day when you plan to have the seminar running.
One way of confirming the availability of a seminar venue would be by making a visit to the offices of the venue managers, and getting the confirmation from them in person.
Another way of confirming the availability of a seminar venue would be by making a phone call to the venue managers, and getting the confirmation in that way.
Yet another way of confirming the availability of a seminar venue would be by emailing the venue managers, and trying to get the confirmation through email. If, for instance, you use Gmail you just need to follow the steps in this article to access your account, and having done so, proceed to compose an email requesting venue availability confirmation. That is an email you can send to the people in charge of the seminar venue and chances are that they will be in a position to respond shortly thereafter, telling you whether or not the venue is available.