To Set the Active Element Template

Click the Element Template drop down icon in the Attributes ribbon group.

A drop-down list of available templates is displayed.
Click the name of the template to be activated, in the drop-down list. The selected template is set as active and the attribute settings in the Attributes group change to match this active template.

Note: Alternatively to activate the element template from the Element Template Dialog, expand the DGN file and the desired template group, right-click the template and select Set Active. The element template becomes active.