You can place your order without an MLS number.
Substitute the street address for the MLS number (123main) or enter a series of letters, etc. It is not advisable to use numbers as it can look like a real MLS number, creating confusion later on. Indicate if the MLS is Valid, Going to Change or Not Needed.
Once you have the MLS number you can update your tour in the Edit Details located on the Tour Preview Page or on your Order List (Manage Tours). Be sure to scroll to the bottom of the page and click on save.