And doing it with styles, it would be like this. The first half wouldn't actually need to run every time. Once the document styles are configured that part wouldn't need to be used again.
Code:
Sub BulletsAndSizer()
With ActiveDocument.Styles("Normal").Font
.Size = 18
.Name = "Times New Roman"
End With
With ActiveDocument.Styles("List Bullet")
.Font.Size = 18
.Font.Name = "Times New Roman"
.ListTemplate.ListLevels(1).Font.Size = 40
End With
Dim aRng As Range
Set aRng = Selection.Range
aRng.Expand Unit:=wdStory
aRng.Style = "Normal"
Set aRng = Selection.Range
aRng.Style = "List Bullet"
End Sub