I'm trying to make one file out of an excel worksheet that has 3
worksheets. I don't want 3 files, I need to make 3 pages. Then I'm
going to convert it to Adobd PDF. How do I make the pages. How do I
attach them to end of each worksheet?

I'm not quite sure what you mean.

If your aim is a PDF file with three pages, I’ve done it this way. It’s not
elegant, admittedly.

Print the workbook to the “Microsoft Office Document Image Writer.” This
opens a “Microsoft Office Document Imaging” window for each worksheet.

Next, combine the worksheets into a single document. To do this, notice
that each of the “Imaging” windows has a left pane with thumbnails of the
page(s). Using right-click, “Copy” one or more thumbnails from the left
pane of one window and “Paste” it into the left pane of another. Repeating
this, the entire document can be merged into a single window. Finally,
print from that window.

Hope this helps.

If you do this sort of thing a lot, you might want to look into
http://fineprint.com/products/fineprint/index.html
for an add-on program that (among many other features) can combine several
print jobs into one, with fewer steps than using Image Writer.