To pre-set the name of the template model, use his key-in:
printpreparation workflow runwizard <PathToTemplatefile>\<TemplateModelName>
For example: printpreparation workflow runwizard D:\ProgramData\Bentley\Map CONNECT Edition\Configuration\WorkSpaces\MapDefaults\printpreptemplates\EastCity.dgnlib\EastCity A1
Note that the location of the template file is defined by MS_GEOPRINTPREP_DGNLIBLIST
This key-in will start the Create Print Model process and put you in the Select Area under Mouse Cursor tool.