it's a manual process to do it on an existing page.
create a recordset to return the data from the TblContactType table
in design, select the ContactType form element and delete it
insert a select list, make sure to set the name to "ContactType"
in the property inspector, click the dynamic button.
set it tot use the TblContactType recordset, use the ID for the value and the name column for the label.
on the update page, click the lightning bolt next to select value equal to and select the ContactType column from the main recordset (not the TblContactType recordset)