That is fairly straightforward e.g.
Code:
Dim strPath As String
'strPath = Environ("AppData") & "\Microsoft\Word\STARTUP\BBTechTemplate.dotx"
'or to account for users who may have moved the startup folder
strPath = Application.Options.DefaultFilePath(wdStartupPath) & "\BBTechTemplate.dotx"
Application.Templates(strPath).BuildingBlockEntries("Ops Tech").Insert _
Where:=Selection.Range, _
RichText:=True