Sequence – This is a number assigned to determine the order in which the forms will appear in both the Existing Forms data table and related applications. 
In the Form Builder, the sequence is how forms should be ordered in the subject visits table.  In this example, notice the forms are in order from 10 to 150.   Good building practice is to have forms in sequences by 5's or 10's in the beginning, so you can add forms in between in future protocol changes.Notice the forms below in the Subject Visits and Events Manager are in the same order as your sequence settings in #1 above.Site type forms and Study type forms can also be set in a sequence within the Site Document Manager and Study related forms respectively.