If it's a one-off, frankly, your best bet is to insert the values manually,
even though there are a lot of them. Another approach if there are not many
rows "missing" from your second sheet would be to add the missing rows, sort
both sheets and combine them. Anything else is probably going to require
that you do a lot of steps you may never have done before.

I don't know Excel well enough to tell you whether or not there is an easy
way to combine your values into a single sheet - I would ask in an Excel
group. However you do it, to do it "automatically", your data will need a
column in each sheet with a common identifier, e.g. perhaps you have a
contact ID or name column that contains the same data for matching rows in
the two sheets. If I were doing it, I'd probably just import the data into
Access and create a query that joins the two tables. But maybe you don't
have Access. In that case, if MS Query is installed on your system (it is
optionally installed when you run Office setup) you should be able to open a
new spreadsheet, go into the Excel Data menu and use Import External
Data|New Database Query. You would then need to work out how to define a
query involving your two sheets (which MS Query sees as "tables") ,
"joining" them using the common identifier column. Then save that sheet and
use it as your merge source.

Peter Jamieson