The wizard will only create pages that handle a single page at a time so you can start with one of these but you will need to add the insert/update for the other table to this page.
The idea is that you start on the page that has the property insert occurring. You can then add to this page a multiple insert for the relating table since there is a one to many relationship.
In the multiple insert you will need to add the form elements for the values you want to insert into this other table, then use the repeat selection server behavior to repeat these form the number of records that you would like to insert into the table. In this new multiple update insert server behavior you would use the id from the property insert, this value is set on the first step of the insert. Whatever you specify as the key field and the session name will be the value that stores this id for you. You just reference this session variable in your multiple insert for your foreign key column.
If you are not familiar with the multiple insert/update/delete server behaviors there are some Solution Recipes that are available on the DataAssist support page here:
Please post back with any questions that you have about any part of this and we will be glad to help you get this going.