You do not state what version of Word you are using but I assume you are
using a custom template. You can change the font the same way as you would
in any other template. Open a blank document using the template. Find the
main style that the other styles seem to be based on and Modify it to suite
your tastes. You do not explain what sort of numbers you are referring to,
but I assume you do not mean conventional line numbering. If you have
numbers along the left margin, such as from 1-25 or so apparently
double-spaced, they are probably in a header or footer. Of course, you have
to make sure that the first line of text on the page matches up with the
first number. To be sure they align as you fill the page up with text you
have to make sure that your line spacing is the same for both the numbers
and the text. Usually this means that you will want to specify an exact
line spacing. My guess is that the numbers already have exact line spacing
provided. This is important because font size affects line spacing, unless
you have specified exact spacing. If you want your modifications to be
available every time you use the template in the future, make sure you check
yes or add a checkmark to Add to Template in the Style menu. One note: I
recommend NOT checking Automatically update; you will save yourself a lot of
headaches.
Hope this helps.
